tirer le diable par la queue

To struggle financially

Describes scraping by financially, living from hand to mouth, rather than a single lucky break or a specific hardship.

Depuis qu'il a perdu son emploi, il tire le diable par la queue.

Since he lost his job, he's been struggling to make ends meet.

It's been around since at least the early 17th century (the lexicographer Oudin recorded it in 1645), though nobody agrees on why. One theory ties it to raking bare fields with a tool called a 'diable' during lean times, another says an empty purse was thought to have the devil sitting inside it.