Moors in Spain, late 700s-early 800s.
Even with Charlemagne leading them against an enemy living in a
hostile land, French are unable to make much progress. Hide behind
Pyrennes until the modern day.

French-on-French losses (probably should be counted as victories
too, just to be fair):

1208: Albigenses Crusade, French massacared by French.
When asked how to differentiate a heretic from the faithful,
response was "Kill them all. God will know His own." Lesson: French
are badasses when fighting unarmed men, women and children.

St. Bartholomew Day Massacre, August 24, 1572.
Once again, French-on-French slaughter.

Third Crusade.
Philip Augustus of France throws hissy-fit, leaves Crusade for
Richard the Lion Heart to finish.

Seventh Crusade.
St. Louis of France leads Crusade to Egypt. Resoundingly crushed.

[Eighth] Crusade.
St. Louis back in action, this time in Tunis. See Seventh Crusade.

Also should be noted that France attempted to hide behind the
Maginot line, sticking their head in the sand and pretending that the
Germans would enter France that way. By doing so, the Germans would
have been breaking with their traditional route of invading France,
entering through Belgium (Napoleonic Wars, Franco-Prussian War, World
War I, etc.). French ignored this though, and put all their effort
into these defenses.

Seven year War 1756-1763
Lost: after getting hammered by Frederick the Great of Prussia
(yep, the Germans again) at Rossbach, the French were held off for the
remainder of the War by Frederick of Brunswick and a hodge-podge army
including some Brits. War also saw France kicked out of Canada (Wolfe
at Quebec) and India (Clive at Plassey).

The French consider the departure of the French from Algeria in
1962-63, after 130 years on colonialism, as a French victory and
especially consider C. de Gaulle as a hero for 'leading' said victory
over the unwilling French public who were very much against the
departure. This ended their colonialism. About 2 million ungrateful
Algerians lost their lives in this shoddy affair.

College Football Season 2020
60% of LSU football team, led by a cross-eyed, squat, foul-mouth, gutter Frenchman of original surrendering stock from Nova Scotia, quit their own team after a couple of early season beatings by Mississippi State and Missouri. They said it was too hard and they didn't want to compete any longer. No one, anywhere, is surprised.

Is this the kind of verification that you were desperately seeking?