The 35-year-old former Manchester United full-back has signed an 18-month contract with the Ligue 1 club after being released from the last six months of his Juve deal.
Evra, who has 81 caps for France, has played only three times for the Italian club this season.
He returns to the French league after 11 years away, having played for Monaco from 2002-2006 before joining United.
"I know Evra well from the French team," said Marseille midfielder Remy Cabella. "He's a captain who binds the group together and talks a lot. He's a great player."
Juventus coach Massimiliano Allegri had nothing but praise for Evra.
"He had a great two and a half seasons with us," he said. "He's a great champion, a great professional and I'm sorry he's left.
"But we talked and we came to this decision. I have only positive things to say about Evra.
"He played for 10 years at Manchester United, he came to Juventus and was a very important player for us."
Evra has featured in five Champions League finals, winning with United in 2008.
He is also a five-time Premier League winner and had two championship medals with Juventus in Serie A.
Patrice Evra has joined Marseille on a free transfer from Juventus.