In the campaign of 1859 he was with General MacMahon at the battle of Magenta at the head of a brigade of Guard Infantry, and again won promotion on the battlefield. Between this campaign and the Franco-Prussian War, he was mainly employed in Algeria, and was not at first given a command in the ill-fated Army of the Rhine. But when the earlier battles revealed incapacity in the commander of the 5th corps, De Wimpffen was ordered to take it over, and was given a dormant commission appointing him to command the Army of Châlons in case of Marshal MacMahon's disablement. He only arrived at the front in time to rally the fugitives of the 5th Corps, beaten at Beaumont, and to march them to Sedan.