Jones, who turned 32 in December and has scored 23 tries in 58 appearances for Scotland, has signed a two-year deal.
"He is an international-class player, a key member of his national team, who has long been playing at the highest European and world levels," said the club's sporting director, Laurent Emmanuelli, in a press release.
The Edinburgh native has been with Glasgow Warriors since 2017, except for a season with Harlequins in London in 2021/22.
He has also spent three years in Cape Town playing for Western Province and the Stormers. He started all three Tests for the British and Irish Lions in Australia last summer.
Jones will bolster Toulon's options at centre where 43-year-old New Zealander Ma'a Nonu and 35-year-old Frenchman Jeremy Sinzelle are out of contract at the end of this season.