Gomis, 30, who scored seven goals in 35 appearances for Swansea last season, has returned to France to join up with the nine-time Ligue 1 winners.
He is the seventh Swansea player to head out on loan this summer following the departures of Kyle Bartley, Matt Grimes (both Leeds), Ryan Hedges, Liam Shephard (both Yeovil), Josh Vickers (Barnet) and Oliver Davies (Kilmarnock).
Source : PA
Source: PA