Complex sentence: After the armistice, "Indomptable" escaped to Casablanca and her mission consisted in neutralize naval activity of Free France in the South Atlantic, however in February 1941 she was attacked by aircraft of HMS "Hermes" and returned to Toulon for repairs.
Split into simpler sentences: After the armistice, "Indomptable" escaped to Casablanca and her mission was to neutralize naval activity of Free France in the South Atlantic. However, in February of 1941 she was attacked by aircraft from the British aircraft carrier, HMS "Hermes" and returned to Toulon for repairs.