Caen were relegated from Ligue 1 after falling to their third consecutive defeat at Valenciennes while Ajaccio's victory at Toulouse was enough to send Franck Dumas' side down.
Caen started the game knowing a victory at their mid-table opponents would almost certainly be enough to extend their stay in the top-flight but Valenciennes were intent on ending the season on a high.
Gaeten Bong created the first chance for the hosts after three minutes when he blazed down the left flank and crossed towards Vincent Aboubakar whose shot skimmed the wrong side of the post.
Ten minutes later Gael Danic also had a chance for Valenciennes when he found space near the penalty area and fired a powerful left-foot shot which was well blocked by Caen keeper Alexis Thebaux.
Caen had their first chance in the 21st minute when Livio Nabab's shot was well saved by Valenciennes keeper Nicolas Penneteau, but the home side went ahead on 36 minutes when Aboubakar headed home after a Remi Gomis corner.
Renaud Cohade came close to extending Valenciennes' lead early in the second half before Danic made it 2-0 from the penalty spot after Gomis was fouled by Thomas Heureux in the box.
Caen gave themselves hope when Benjamin Nivet fired home on 77 minutes, but Renaud Cohade was sent clear to make it 3-1 to Valenciennes four minutes from time, and the news from Toulouse confirmed Caen's fate.