Toulouse climbed to seventh in the Ligue 1 table after two goals in 10 frenetic first-half minutes helped secure all three points for Alain Casanova's men.
Guinea international Fode Mansare gave Toulouse the lead before they doubled their advantage shortly after Daniel Braaten's deflected shot found its way into the back of the Le Mans net.
Anthony Le Tallec netted just after the half-hour mark but Le Mans failed to build upon their goal and Toulouse held on for all three points.
Le Mans started brightly when Ibrahima Camara volleyed a shot from an inswinging corner which stung the fingertips of Toulouse goalkeeper Cedric Carrasso.
On the 10-minute mark Braaten broke down the left flank to cross to an unmarked Mansare on the edge of the Le Mans penalty area to coolly slot home beyond goalkeeper Yohan Pele.
Barely nine minutes later the lively Braaten again broke free down the flank to fire a testing shot which deflected off defender Saber Ben Frej and into the back of the net.
But Le Mans midfielder Le Tallec headed home from a Mathieu Coutadeur cross on the half-hour mark to give Yves Bertucci's men some hope before the break.
The hosts continued to press and could have grabbed a well-deserved equaliser when, after good interplay between Coutadeur and Gervinho, Coutadeur found himself in acres of space only to see his effort well saved by Carasso.
However, Toulouse could have extended their lead just after the hour mark when a well-worked free-kick taken by Etienne Didot spooned just inches over the crossbar.
With full-time looming, Toulouse continued to dominate and should have claimed the victory in the 79th minute when a drilled effort from Cheikh Mbengue was superbly blocked by Pele.
