Paris, an entrenched camp, was defended in 1914 as provided for in the 1909 siege war instruction. The application of this text to Paris is a little peculiar since the city is surrounded by a triple belt of fortifications: the continuous enclosure of approximately 32 kilometres of tower comprising 94 bastions and then, at a variable distance, a first belt of forts, known as detached, built at the same time as the enclosure, from 1840 to 1845. Finally, the belt of forts Séré de Rivières was built from 1874 to 1880. Let us mention a few names to specify the locations: Issy, Vanves and East forts for example for the former, Vaujours, Saint-Cyr and Villeneuve-Saint-Georges forts for the latter.

The Séré de rivières forts were built after the War of 1870 to prohibit the implantation of enemy artillery batteries, as the Prussians had done at the end of 1870. The artillery of 1870 was no longer the artillery of 1840 and the detached forts did not prevent the Prussian batteries[1] from firing on the town (especially the southern part).

What is this triple crown of forts or fortifications in 1914 worth? Not much, for several reasons. The continuous enclosure [2] consists of a continuous ditch 10 m deep and 15 m wide whose walls, escarpe and counterscarp, are extended by horizontal surfaces forming glacis and parapets. It cuts into the city of 1914, which has expanded on both sides due to the lack of space elsewhere for its growth. Since 1870, and even a little earlier, the owners who had been robbed by the bans on building in the easement areas had formed leagues and unions to put pressure on the civil, and indirectly military, authorities to decommission the enclosure and reclaim the land. The city of Paris is ready to take advantage of the windfall, and is also considering juicy real estate deals on condition that it pays the Ministry of War as little as possible[3] for the land.

The detached forts were built in stone (millstone), whitewashed and could not withstand modern artillery. The Séré de Rivières forts were also built of stone, but the barracks were buried and the living works were protected by layers of earth 3 to 4 m thick. The cannons, with 30 to 60 guns, are normally placed on top of the forts, in the open air, and protected laterally by crossbars. At the same time as new forts were being built, new guns were designed and built to arm them. These were the de Bange guns, 120 mm long, 155 mm long, 220 mm and even 270 mm mortars.

In 1886, when the last Séré de Rivières forts were being built, Turpin, a chemist from the Lépine competition, invented a very high explosive: melinite. It had been known for a long time, but Turpin managed to stabilize it without preventing it from detonating. Experiments are carried out on a brand new fort, the Malmaison fort. The masonry was dislocated, the vaults collapsed and the guns on the artillery "crests" were dismantled and destroyed; a few shells were enough to make the fort untenable. From 1890 Paris could no longer take shelter behind its fortifications.

What could be done? Several solutions are possible: take the guns out of the forts and install them in detached batteries of 4 to 6 pieces, improve the protection of the forts by using concrete and, better still, reinforced concrete which comes fromFinally, to keep artillery in the forts but installed in turrets, "armour" as it was said at the time, armed with one or two pieces. These steel cast iron turrets are rotating of course, but also eclipse. We will do a bit of all this but the design is such that in Paris we do nothing or almost nothing except install 5 turrets on some forts: Palaiseau for example. The concreting of the structures is reserved for the forts in the east: Verdun, Toul, etc..

It was therefore necessary to conceptualize a defence of the squares [4] that took into account the new constraints; this was the subject of two successive instructions on siege warfare, that of 1895 and that of 1909, which codified the way of attacking and defending the squares. And the defence of Paris, an entrenched camp but also a place of war, will be studied and implemented according to the precepts of the regulatory texts.

In April 1914 the last defence plan for Paris, which had many ups and downs, was approved by Mr Étienne, then Minister for War. It provided for the creation of three zones all around Paris, on a little less than 200 kilometres in circumference: north, east and south-west separated by three intervals: south (Haute-Seine valley), west (Basse-Seine valley) and north-east (Roissy region, route of the current A1 motorway). Each of these areas is divided into sectors, eight in total, plus a ninth one covering all the intervals.

The defensive organisation around Paris at the end of August 1914.

The artillery batteries are scattered in the sectors and bear a number starting with the number of the sector. For example, in sector 5 from the current A4 motorway to Villeneuve-Saint-Georges, there are sixteen batteries numbered from 501 to 516 in the trigonometric direction.

The artillery must be dispersed all around the Capital at a variable distance of 12 to 14 kilometres in batteries of 4 to 6 pieces. A little ahead are trenches, protected by wire networks and occupied and defended by territorial infantry divisions.

The installation and dispersal of the batteries began on 3 August 1914. Everything had to be done, as peacetime forbade working on land that was almost exclusively private. The pieces come from the parks of Place, Versailles, Vincennes and the forts where they are, for some still, stored and must be driven to post by couplings. If, as a result of the many reconnaissance surveys carried out over the years, we know perfectly well where they will be placed in batteries, nothing has been done to date and the land has not been prepared.

In parallel with the installation of the guns, ammunition stores had to be set up: central, sector and battery stores. The supply was to be done by trains running on 0.60 m or 0.50 m tracks. These trains were pulled by horses, or even by men, but also by special locomotives called Péchot locomotives named after Colonel Péchot who designed the system [5]. All these tracks must be laid directly on roads, paths and trails.

The personnel are, for the most part, provided by the Territorial Army Reserve (RAT). They will arrive at the drop count in the first fifteen days of mobilization. It is planned to use 8 reserve batteries and 17 territorial batteries, each with 315 men, which will be reinforced by 25 additional 200 men to bring the batteries up to 500 men. The artillery personnel have a triple role: to install the batteries and stores (including the necessary earthworks but in cooperation with the engineers), to install the 0.60 track and finally to serve the guns.

And it's not a sinecure! Installing the parts means: digging 4 or 6 earthworks about 2 m deep. Each one is flanked by mud walls (which, playing the same role as the crossbeams of the forts, bear the same name) covered with rafters to prevent the earth from collapsing and is finished by a shoulder of the same height behind which the coin will be placed in a battery. Then a platform consisting of three bunk beds of planks stacked one on top of the other must be installed on the platform, which weighs about 6 tons and requires at least 6 hours of work to be perfectly adjusted. The cannon is placed behind the shoulder on the platform. In 1914 the platforms are all equipped with a hydraulic brake fixed on a fifth wheel which we will speak about later.

All around the room various works are going to be installed: battery commander's PC, protection trenches, finally battery stores (in principle 100 shots per piece, a little less for the more important calibers) and observatories as close as possible to the rooms in order not to have to use rare and unreliable telephone lines.

In total it takes at least a fortnight to completely install a battery. So there is no question of changing location. An essential difference between heavy field artillery and siege artillery is the almost total lack of mobility of the second compared to the first. The instruction also provides for one or two locations, no more, before the final attack in the case of siege and none in the defense of places. In other words, the batteries installed on their positions are made to remain there whatever the enemy does.

As long as the 0.60m track is not laid and the magazines finished, nothing is finished and it is impossible to fire for lack of shells and gargoyles except for the few shots that accompany the pieces. This will be the most difficult task. The 0.60 route was abundant in the entrenched camp (quarries in particular) but, anxious not to stop all industrial activity, the Minister would take a long time to authorise the re-establishment of the 0.60 route.It will take a near tour de force for the artillery command to be able to announce on 30 August that each gun is supplied at about 30 to 40 rounds, i.e. about two hours of fire, but without being able to replenish the stocks.

What are the guns? Essentially of the 120 and 155 mm L[6] of Bange. There are also some 155 mm C[7] from Bange and more rarely 95 mm Lahitolle. The 155 and the 120 look like brothers; they are made of steel and are loaded by the breech. The first weighs in working order about 2,700 kg and the second 5,700 kg, and to carry them they have to be split into separate bundles; the striped part is about 20 calibres long in both cases. The projectile of the 155 weighs 43 kg (which "wears out" the servants) and the range can reach about 8 km (at the time; we will do better later). The projectile of the 120 gun weighs only 20 kg, goes as far and the piece is much more handy which explains its greater diffusion. These guns, well served, theoretically fire about 1 shot/minute.

The great challenge of the end of the XIXth century is the control of the recoil. The de Bange guns are equipped with a hydraulic brake consisting of a piston linked to both the platform (fifth wheel) and the stock of the stock. It compresses a liquid, by definition incompressible, which can only escape through carefully calibrated nozzles. The barrel then recoils about 90 cm and, as it recoils, rises on recoil wedges which act as a recuperator since the barrel returns by gravity to its battery position (see picture above).

What do the guns fire on? Except for area shooting, which is generally inefficient and consumes ammunition, all targets are spotted: crossroads, bridges, roads, forest edges, etc. It is unthinkable to fire on a target that would suddenly reveal itself because you don't know how to do it. The display of the firing elements is a long and delicate operation where tools are used, in particular for the direction of the guns, as precise as crowbars ! Masked fire has only been known for about twenty years but many gunners still doubt their interest. The pointing practiced remains the traditional "upward" pointing which requires to see the objective. The lack of an "ad hoc" cartography, in particular, at the beginning of the war, the absence of grid, forbids to locate the points of the ground by coordinates ! One will quickly add a grid on the maps but as the origins are not the same it is impossible to connect two shooting logs. The projection used is the Bonne-Panthéon projection (meridian of Paris), the one of the staff map. Later, the Lambert projection will be used systematically for all French armies.

The sight setting practically forbids firing from more than 3 to 4 km away and even more, provided the weather conditions allow it. Quite soon, however, aerial observation will be used to observe and correct the firing, from the end of September 1914, in Camp Retranché. The theoretical range of de Bange's guns was therefore not very meaningful[8], especially since no cannon had ever been fired or adjustments made in the entrenched camp. In case of German attack all was to be done. The track of 0.60 will take a long time to be deployed and it will reach a maximum of 250 km at the end of 1914.

Finally what was the result? On 26 August 1914, 73 batteries were in place; in October, well after the danger had passed, 99 batteries representing 534 pieces were installed all around Paris and there would be no more. With what efficiency? Here is what General Desaleux wrote commanding the artillery of the Retreating Camp a few months after the Marne.

"If,at that date, almost all the guns had been put into batteries, if most of them could indeed fire with a limited supply, the delay in the organization of the fire and the lack of training and experience of the personnel allowed only very uncertain results to be expected".

It is clear that the Germans could have captured Paris relatively easily. The precepts of siege warfare, applied without any nuance by Gallieni, prevented the strengthening of defences against dangerous directions. Not a single gun failed to meet the requirements of the Haute-Seine, which was never threatened. To want to protect oneself in all directions, one could not protect oneself anywhere!

It was the Battle of the Marne and the manoeuvre that saved Paris. The Retranché Camp had nothing to do with it, but it wasn't until 1917 that we realized the failure of a custom-made concept to save what could be saved from permanent fortification. A fragile parenthesis since the same heresy would rise from its ashes a few years later and find its fulfillment in the Maginot line with the consequences that we know.

1] Steel and breech loading cannons for the Prussians.

[2] On whose site the ring road was built.

[3 ] At that time, there was a kind of "Mission for the Realization of Real Estate Assets".

[4 ] No one will be bold enough to draw a definitive line on the permanent fortification. In 1914, 23% of the troops were mobilized in the strongholds. Contrary to what all the thurifiers of the fortification claim, it is not an offensive doctrine that "plummets" the French army at the beginning of the war, but rather the weight of the past!

5] It is indeed a system with many equipments that it is not a question of describing here.

[6 ] Long.

[7 ] Short.

8] The quasi exclusiveness of the 75 mm to the detriment of a heavy artillery was not, in 1914, as absurd as one wanted to say it.