The 22-year-old, who started his senior career with France Pro D2 League side Stade Montois, did have a short spell in England last season with National Two South side Bury St Edmunds, where he made seven starts and one replacement appearance in four months.
After leaving Bury St Edmunds the 5ft 5in player went to New Zealand where he played Green Island RFC.
The Frenchman looks like he will be a replacement for Plymouth-born Cameron Setter, who broke his leg in Albion’s final home match of last season without having been offered a new contract at Brickfields for the 2016/17 season.
Albion already have Matt Shepherd and Jack Maunder who can play nine.
Le Roy, who has been training with Albion for a couple of weeks, said: “My agent set up the move to Plymouth and I’ve been very impressed with the facilities at the club.
“Plymouth Albion are an ambitious club and I know I’ve joined a good bunch of lads.”
He added: “I would describe myself as an energetic scrum-half who likes to play a running game keeping the ball alive whenever possible.
“From what I have seen Plymouth have some very good players and I can’t wait for the season to start.”
Albion have said their squad is now almost complete, with only ‘two or three more players’ likely to join before the club start their pre-season matches.