French sailors - or
marins-fusiliers as they were then called - wore their standard naval uniform when formed into ad hoc landing parties. Below is an period sketch of a French sailor in the Crimea drawn in 1855 by captain (later general) Vanson aboard the French flagship
Montebello.

Despite the introduction of soft fatigue caps, the broad-brimmed naval hat appears to have been the most common headgear for the rank and file, while officers wore peaked caps. Packs could also be worn in action when operating away from the ships :


Also remember that
marins-fusiliers landing parties were quite distinct from the
Infanterie de marine, who no longer served aboard ships from 1856 and were effectively colonial infantry rather than marines. The 4th infanterie de marine regiment did serve in the Crimea, though, being part of the 1st brigade, 3rd division, 2nd army corps under general Bosquet. Below is a pic showing a
marsouin (as
infanterie de marine privates men were called) next to a sailor. He is wearing his regulation
paletot, a double breasted frock coat with the yellow epaulettes that were the naval infantry's trademark, though shell jackets were also used in hot weather.