Domenech, back in a club coaching role for the first time in 27 years, was named as Christian Gourcuff's replacement on Dec. 27, 10 years after his France side were knocked out in the first round of the 2010 World Cup in embarrassing fashion.
At the tournament in South Africa, France players went on strike after Nicolas Anelka was kicked out of the squad for insulting Domenech, whose contract was not renewed after the debacle.
The 68-year-old Domenech, who last coached at club level at Lyon from 1988-93, had been in charge of Les Bleus since 2004, leading them to the World Cup final in 2006.
Wednesday's result extended Nantes' winless run to nine games, leaving them 17th in the table on 16 points from 18 games.
Rennes are fourth with 32 points.