PSG host relegation battling Le Havre on Saturday
Mayweather, 43 and with an unblemished record of 50-0, last fought professionally in August 2017 when he won by TKO over mixed martial arts champion Conor McGregor, who was making his boxing debut.
The five-weight division world champion said he will step into the ring on Feb 20 at a yet to be determined venue to face Paul, who has a record of 0-1, with that loss coming against fellow YouTuber KSI.
The fight is the latest exhibition bout featuring ageing former-champions and celebrities.
Former-heavyweight champion Mike Tyson, now 54, returned to the ring last month to face Roy Jones Jr in a charity exhibition bout that was ruled a draw.