The infinitive-based deverbal nouns the other answers mentioned aren't very productive anymore except in some specific registers, mostly scholarly works of philosophy and psychology. That is, nouns like le manger, le parler or le coucher started being used during a previous stage of the language and are now part of the French lexicon, but speakers are rather unlikely to spontaneously create a new word like "le fumer" for the action of smoking, for example.
Part of the reason is that the infinitive, originally a type of deverbal action noun, has been becoming since pre-Latin times more and more verb-like in usage, eventually losing almost completely its availability as a noun.
The other answers concentrated a lot on the infinitive, but unlike the English infinitive, the French is marked by a suffix. There is however a verbal form that's phonologically a bare stem: the singular indicative present.
And as it happens that it's very common for the bare root of first group verbs to be used as an abstract noun, and this process is fully productive, creating nouns phonologically identical to verb forms.
Following the model of well established vocabulary items like:
- Avancer -> l'avance (to advance -> the advance)
- Danser -> la dance (to dance -> the dance)
- Tremper -> la trempe (to drench or soak -> the mettle (from the action of soaking red hot metals in water, which affect the quality of the metal)
- Laisser -> la laisse (to let -> the leash)
- Marquer -> la marque (to mark -> the mark)
Speakers coin new nouns all the time:
- Aguicher -> l'aguiche (to seduce -> the act of aggressively teasing)
- Gagner -> la gagne (to win -> the win)
- Vaper -> la vape (to vape - ?the vaping)
- Bouffer -> la bouffe (to eat -> the food) (first attested in print in 1921!)
The existence of another noun of the same meaning inhibits the creation of those suffixless deverbal nouns, but doesn't block it completely, as exemplified here by la gagne, whose birth wasn't completely stopped by la victoire (it's however, at least for now, used in a lot less contexts than victoire).
As you've probably noticed, those nouns are all feminine. There existed old suffixless masculine deverbal nouns like porter -> le port or chanter -> le chant, but they aren't productive anymore, probably because sound changes like the loss of the final /t/ of those words have muddled the etymological link in speakers' minds.