He was available on a free transfer and becomes Les Verts' second acquisition of the summer, following the signing of playmaker Renaud Cohade from Valenciennes.
Boss Christope Galtier was looking for a right-back as a priority after Albin Ebondo cancelled his contract and youngster Loris Nery joined Valenciennes.
Clerc, 29, came through the ranks at Lyon, for whom he played over 150 matches.
The 6’2” full-back lost his place to Anthony Reveillere though, and joined Nice when his contract expired two years ago.
He made 61 league appearances with the Cote d’Azur side, scoring five goals.
Clerc, who can also play in midfield, made 13 international appearances for France.