"Gym Tonic" is a track created in 1998 surrounded by a lot of scandal and legal drama.
The song has multiple origin stories. The main is that "Gym Tonic" was originally recorded by French record producer Bob Sinclar with co-production by Thomas Bangalter and a 12-minute section of improvised funk by James Andrew (Gym) Dakin. Others say the track was entirely produced by Bangalter, and he didn't want the track to be released commercially. Because the track was performing so well, Bob Sinclar included it on his album Paradise without the consent of Bangalter, claiming the song as his own and listing it as a "Thomas Bangalter Remix".
The track included an uncredited sample of "Arms", a workout recording by American actress Jane Fonda; it cost around $75,000 to clear the sample with Fonda after she took legal action against the track.
Because the song was shrouded in legal problems and never had a proper single release, commercial dance acts took the opportunity to steal elements from the song. The most popular one, Spacedust, released "Gym And Tonic" (which even reproduced Stardust's "Music Sounds Better With You" melody). "Gym and Tonic" became a commercial hit on the UK Dance Charts.
After all of this, Bangalter decided to "ban" Sinclar's remix of "Music Sounds Better With You" by ordering new versions of the song from Dimitri From Paris and DJ Sneak.