The 22-year-old, who scored five goals in 45 appearances for the Pilgrims last season, has agreed a two-year contract at Adams Park.
Manager Gareth Ainsworth told the club's official website: "Paris is a player we've been watching for a while and he impressed in both games against us last season.
"He's quick and tricky and will add another dimension to our attack. I'm sure he's a player that our fans are going to enjoy watching.
"I'm delighted he's agreed to join us and I'm looking forward to working with him."
Cowan-Hall, who came through the ranks at Portsmouth before spells with Grimsby, Scunthorpe, Rushden and Woking, added: "It was a no-brainer for me and it's somewhere I'm wanted as well."
"He (Ainsworth) told me the ethos and what the boys were like. Wycombe won in Plymouth last season and I know the guys work hard.
"He told me the way he wanted to play and he wants to play football - it was an easy sell!"