Toulouse's Champions League chances have received a blow following their 2-0 defeat at Valenciennes.
The visitors created the better of the first-half opportunities, with Nicolas Penneteau forced into action to deny Moussa Sissoko in the 20th minute.
It became an uphill struggle for Toulouse after Franck Tabanou was sent off on the stroke of half time.
The midfielder saw red for a reckless challenge on Mathieu Dossevi.
Valenciennes made their advantage count in the second half and took the lead through Gael Danic's 62nd-minute strike.
Mamadou Samassa wrapped up the victory from the spot in the 89th minute after Etienne Didot had brought down Remi Gomis.
