Garande, 59, joins the club amid its sale to an American investment fund and a court case fighting its relegation from Ligue 1.
"Toulouse FC and all of its supporters welcome Patrice Garande to the club," said a statement on the club's website.
Garande turned out for a string of French first and second division outfits during a 17-year playing career which ended in 1994.
His life as a coach began at fourth division Cherbourg in 2000. He led the side to promotion in 2002 before heading to second division Caen as an assistant coach.
As head coach, he steered Caen into Ligue 1 in 2014 and was at the helm for four top flight campaigns before quitting in 2018.
Mission: possible promotion
Another promotion surge may be in the offing at Toulouse if the club loses its appeal against a Ligue de Football Professionnel decision to declare the season over early due to the coronavirus pandemic and relegate it to Ligue 2 along with Amiens.
The clubs took their fight to the Conseil d'Etat who told the LFP to suspend the demotion and to consider a Ligue 1 with 22 clubs instead of 20.
However the LFP's general assembly is expected on Tuesday to confirm a Ligue 1 with 20 clubs for the 2020/21 season.
