The 20-year-old has come to Selhurst Park in search of first team action, and has signed in time to be available for tonight's home match against Watford.
"I want to show people what I can do here. It's going to be tough to get into the team but I do hope to get some games," he told the official site.
"I can play on the right and the left. I like to run at defenders, I'm tricky, quick and like to put in crosses.
"If everything goes great then I could be here longer."
The young Frenchman was at Barcelona before joining Portsmouth in 2005. He has previously been out on loan at Bournemouth and Preston.
In a squad shake-up, Warnock has also made youngsters John Bostock, Lee Hills and Moses Swaibu available for first team selection. Midfielder Bostock is just 15 years old and would become the youngest player ever to represent Palace should he make his debut tonight.
Hills, 17, will put pressure on Tony Craig for the left-back spot, while 18-year-old Swaibu plays at centre-back.