The 29-year-old will earn a reputed 700,000 Euros per year and has an option within his contract to leave after one year - or extend for a third term.
He will join a host of newcomers at the big-spending French Top 14 side. Philippe Saint Andre has switched from Sale Sharks to become director of rugby and Wales and Cardiff Blues centre Jamie Robinson could line-up outside Wilkinson.
Tom May, a team mate for many years at Newcastle, will join Wilkinson in the south of France, along with the Sale duo of Sebastien Bruno and Juan Fernandez Lobbe, Saracens' Kris Chesney is also joining, along with Bristol flanker Joe El Abd. "Jonny is very motivated. He has undergone some tests because we want to make sure he is 100 per cent fit when the season starts," said Saint Andre.
"He is a player who scores when the team dominate and who reassures his team mates when they suffer."
A fluent French speaker, Wilkinson scored almost 2,000 points in 174 games for the Falcons. He joins a growing list of English internationals heading to France next season.
They include British & Irish Lions centre Riki Flutey, London Wasps forwards Tom Palmer and James Haskell and Gloucester full back Iain Balshaw.