'Mousquetaire' was a French unrealised undertaking to capture the German pocket centred on the ports of La Rochelle and La Pallice on the west coast of France (April/May 1945).

La Rochelle was a major German naval base on the Atlantic, especially for U-boats which were based in huge reinforced concrete pens all but immune to the heaviest Allied bombing. Right up to the end of the war, La Rochelle was, together with other west-coast ports such as Royan and St Nazaire, held by the Germans after being bypassed by the main thrusts of the Allied land campaign after 'Overlord' and 'Dragoon'.

The German pocket centred on La Rochelle was an area with a radius of some 6 miles (10 km) round La Rochelle, reinforced by an anti-tank ditch. After 'Overlord' and subsequent operations in Normandy, many German troops had regrouped in the area, which was taken under Allied siege in September 1944 in much the same way as other Atlantic seaboard ports such as Brest, St Nazaire, Lorient and those of the Gironde river estuary, but not subjected to any major land or attack in the period up to May 1945.

The Allies have no urgent need for the port, which the Germans would undoubtedly have destroyed if they felt there were on the verge of local defeat, so it was considered more sensible and certainly less costly merely to contain the base.

Adolf Hitler and elements of the German high command wished to keep control of the coastal garrisons, and therefore rejected all notions of an evacuation, in order to maintain a threat to Allied shipping in the Atlantic. A French civil population of 39,500 came under the control of Vizeadmiral Ernst Schirlitz, the Kommandierente Admiral 'Atlantikküste', who also had 22,000 German military personnel under his command. During the siege the Allies still allowed electricity, wood and some supplies to be delivered in order to alleviate the ordeal of the civil population.

The Free French command was opposed to this passive attitude, however, and wished to take these coastal cities by force, mostly for considerations of national pride. Agreements between the French and the German occupation force in La Rochelle exchanged a French promise that there would be no attack with a German undertaking not to destroy the port installations of La Rochelle and La Pallice. With its harbour facilities damaged in air attacks, La Rochelle could not be used for the launch of a U-boat offensive.

La Rochelle escaped the 'Vénérable' fate of Royan as the latter was considered the higher priority as it commanded the Gironde river estuary and thus the approaches to the great port of Bordeaux. The French and US seizure of Royan was followed by the 'Jupiter' (iii) capture of the Ile d’Oléron, and Général de Corps d’Armée René Marie Edgar de Larminat, commanding the French forces in western France, was planning 'Mousquetaire' against La Pallice at the time of Germany’s surrender in May 1945.

The French units which participated in the operations against the German pockets on the west coast of France included local resistance groups as well as the 50^th and 158^th Régiments of Général de Division André Marie Martial d’Anselme’s 23ème Division de Marche d’Infanterie (also known as the Division de Marche Oléron), Général de Division Philippe François Marie de Hauteclocque’s (Leclerc de Hauteclocque’s) 2ème Division Blindée and the 4ème Régiment de Zouaves.

La Rochelle was the last French city to be liberated, and its German garrison surrendered only 7 May.