proverb/il nə fo pa vɑ̃.dʁə la po d(ə) l‿uʁs a.vɑ̃ d(ə) l‿a.vwaʁ tɥe/
don't count your chickens before they're hatched
Literally, “one must not sell the bear's skin before having killed it”. From the fable L'Ours et les Deux Compagnons by Jean de la Fontaine.