Macha from the TV series Tout sur moi uses an informal expression below, one that amounts to swearing in French:
Y fait beau en esti!
It’s fuckin’ beautiful outside!
[Said by the character Macha in Tout sur moi, “Addict!,” season 4, episode 4, Radio-Canada, Montreal, 6 October 2010.]
Y fait is just an informal pronunciation of il fait.
Now let’s look at the fun part! Esti comes from the word hostie, the French name of the sacramental bread used in the Catholic Church. En esti means “like hell,” “a hell of a lot,” “fucking,” etc., and is sometimes used after an adjective to make it stronger in a vulgar way.
Maybe you’ll want to avoid using en esti yourself for now because it’s vulgar… unless you really do want to swear in French because it’s just so beautiful out that you can’t control yourself!
More examples, this time with cher:
cher en esti
C’est cher en esti!
It’s goddamn expensive!
Tu l’as payé cher en esti!
You paid a lot of fuckin’ money for it!