Gradel joined the Stadium Municipal team during the past summer window, after he had failed to gain a regular first team place at the Premier League club.
The 30-year-old managed 27 starts and two substitute appearances in Ligue 1 this season, scoring eight goals and getting a single assist.
He took to social media to thank the club.
"Thank you very much to Toulouse FC, the president, Pascal Depraz, [coach] Michael Debeve, the players, the staff as well as the supporters," Gradel tweeted.
"Mission accomplished tomorrow will be better."
It is unclear whether Gradel will stay at Bournemouth or try to find another club.