The Fontainemelon 90-5 is a mechanical watch movement with an automatic winding system. It features a sweep second function and is designed with a large balance and low profile due to its indirectly driven minute setup. The differences between the Fontainemelon 90-5 and its counterparts, the 2375 and 2379, are not known, including the assignment to different rotors, which could involve a single part or a separate sinter-metal weight.