The French War minister, Edmond Le Bœuf, had made plans for the creation of three armies at Metz, Strasbourg and Chalons .The army of Strasbourg would be commanded by Marshall MacMahon ( of Irish ancestry), hero of Crimea and Governor of Algeria.All the troops which could be spared from Algeria would be sent to this army, which was to be made of three corps. The army of Metz, would also have three corps, commanded by Marshal Bazaine, the leader of the recent failed Mexican expedition. The army of Chalons, with two corps, would be under the command of Marshal Canrobert.
For five days all preparations were made on this plan, then on July 11, the emperor ordered that one large army, eight corps strong and under his personal command, which would gather in Metz .The three marshals, would command one corps each .Napoleon made these changes, expecting Austria would join the war on his side as well. Most Austrians, were rather surprised at what they considered premature declaration of war, for which they were unprepared .Russia, also threatened to mobilize to aid Prussia, if Austria mobilized . Austria was to declare neutrality on July 20th.
The French mobilization was chaos . French troops were scattered all over the country .There was no great organizer like Moltke in France .Leboef decided that mobilization should take place at once rather than successively to be able to launch an attack before German could bring their massive armies together. By August 6, only half of the reservist had reached their units and many lacked equipment and uniforms . Many were stuck in railway stations due to rail delays .
Most of the French command had served in Algeria in their formative years and this influenced the command style, with ambushes being common and a desire to seek a strong defensive position.France had been fighting in Algeria for 30 years by the time the war started .
Strasbourg was the base of operations for the French right, and Metz for the center and left. Besides Strasbourg and Metz other frontier fortresses strengthened the advanced line — Bitche and Phalsbourg in the Vosges, and Thionville on the Moselle. The French army occupied, therefore, a very long line, and its advanced corps, extending from Thionville on the left to Strasbourg on the right, were scattered over too wide a front, insufficiently connected, and too far from their supports at Metz .
