There are approximately two bands that use this name: 1) A 7-piece sludge band from Lyon, France which began as side-project to Donefor in 2001. So far they have released 2 albums and 5 splits.
The current line-up consists of Pierrick (guitar), Benjamin (drums), Tiphaine (keyboard, electronics), Xavier (vocals), Marrion (bass, backing vocals) and ex-Bad Taste members Antoine (aka Scotch, guitar) & Arnaud (aka Pignolo, vocals). Official site: http://www.destroyalldreamers.org. 2) An Italian space rock band led by Marco Ranalli, founder of Insider.

Read more about Overmars on Last.fm.