Paris Gun/ lange 21cm Kanone in Schiessgerüst/ long 21-cm gun in firing platform

The lange 21cm Kanone in Schiessgerüst (long 21cm gun in firing platform) or Paris Gun was a very long range railway gun that was just about able to hit Paris from positions behind the German lines, and caused a brief panic when it first entered combat in 1918.


The idea of producing a very long range gun was triggered by a series of ballistic trials in which the shells travelled much further than had been calculated. The reason for this was that the large guns involved fired their shells so high that they left the thicker parts of the atmosphere, allowing them to travel long distances in the thinner air of the upper atmosphere. It soon became clear that this effect could be used to produce a gun that could just about hit Paris from the part of the German lines nearest to the French capital. The Germans were planning a spring offensive for 1918 which would bring the gun closer to Paris and improve its effectiveness, and so despite the vast amount of effort that would be required, work began on the Paris Gun. It was designed by the same man as the 420mm 'Big Bertha'. 

The new gun used a very long 210mm (8.27in barrel) that was mounted inside a shorter 380mm (14.96in) naval gun. The long narrow 40m long barrel was prone to bending under its own weight, and so have to be externally braced, giving the gun a rather peculiar look. Later barrels were built with a calibre of 232mm, but in both cases the barrels wore badly each time the gun was fired, so a series of carefully designed shells had to be produced, each slightly wider than the last. The gun required a massive firing platform, long and narrow, with space for the breach in the middle. It had a naval turntable at the front of the platform and racers on tracks at the rear. The entire structure was built onto a solid timber foundation, and the area then concealed within a forest.

Combat Record

The first firing position for the Paris Gun was in the Crépy region, 75 miles from Paris. The first bombardment began on 23 March 1918. At 07.30 there was an explosion in the Quai de Seine, in the north-east of Paris, apparently without any cause. At 7.50 there was a second explosion in the Boulevard de Strasbourg, in which eight were killed and thirteen injured. This time some shell fragments were recovered, but at first an air raid was suspected (although no aircraft had been seen). The third explosion came in the Rue de Chateau-Landon, and the fourth in the Rue Charles-Cinq, where another person was killed. By now it was clear that some sort of long range gun was involved, and the French investigations quickly came to the conclusion that the shells came from a 208mm gun, probably somewhere around Crépy.

The first bombardment caused a great deal of panic in Paris. Many of the citizens fled from the city, unnerved by the random nature of the bombardment. The gun was operating at the extreme limits of its range, and was very inaccurate, so the bombardment had limited practical impact, but the impact on the morale of Parisians was much more significant. It was also capable of inflicting heavy casualties with an unlucky hit - on 29 March (Good Friday) 82 people were killed when a shell hit the Church of St. Gervais on the Ile de France.

The Paris Gun had two main weaknesses. The first was that each time it fired, the heat generated in the long barrel slightly increased its calibre, until after only sixty shots the barrel was worn out. This also meant that each shell had to be slightly larger than the last in order to fit tightly into the ever-wider barrel. The shells had to be fired in the correct sequence - if too large a shell was used, then it could explode in the barrel. The second was that in order to hit Paris it couldn't located too far behind the German front lines. As a result normal French heavy railway guns were able to fire into the area where the gun was based. The Germans had to replace the barrel once while it was still at Crépy, but their reaction to the second problem was to move it.

The German spring offensives had pushed the front line west to Montdidier. The Paris gun was moved to the Bois de Corbie, from where the second bombardment began in April. This time the range was shorter and the gun thus more accurate, but once again it came under fire from French railway guns. This time the location was discovered, and the shell fire caused a number of casualties amongst the gun crew. Life was also beginning to return to normal in Paris, where the population got used to the limited threat from the comparatively small shells.

A third position for the gun was constructed at Beaumont, this time with lavish rail connections and a steel foundation. The larger 232mm gun barrel was used from Beaumont, and the gun continued to perform well technically, but it was becoming increasingly irrelevant. The German offensives were running out of steam, and a scattering of shell hits on Paris could do nothing to alter that.

In July the gun was moved again, to the Bois de Bruyères, where a fourth bombardment began on 5 July. By now there were two or possibly three guns, although only one was ever in use at a time. By now the gun was irrelevant - in August the Allies went onto the offensive, at the start of the victorious '100 days', and the Germans were soon forced to retreat too far for the Paris gun to be able to hit the city. The allies found the firing platforms as they advanced, but the guns themselves disappeared. They probably played a part in the development of some of the even heavier German guns of the Second World War,


21cm Cannon L/162 (Paris or Wilhelm Gun)



Barrel Length

33.91m (L/162)

Weight for transport


Weight in action

1,490 tonnes


0 to 55 degrees


60 degrees

Shell Weight


Muzzle Velocity

1,425-1,646m/ sec

Maximum Range


Rate of Fire

1 round every 2 minutes

German Artillery 1914-1918, Wolfgang Fleischer. Covers over 100 guns used by the German Army and shore detachments of the Navy during the First World War, a conflict largely dominated by artillery. Each one gets a brief description, a set of technical stats and a good picture. Shows the wide range of gun types and sizes used by the Germans during the First World War, and the way in which they evolved to deal with the unexpected challenges of trench warfare. [read full review]
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Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (2 August 2018), Paris Gun/ lange 21cm Kanone in Schiessgerüst/ long 21-cm gun in firing platform,

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