You might want to look at remote work, if that's something you're comfortable with. You can get paid well (think "Paris-salary") and live in more economical areas. Happy to talk more if you're interested.
In the UK my experience has been that graduate developer salaries aren't that great, but can double for someone woth as little as 1-2 years experience post university.
But unless the job is in Paris (which is extremely expensive) I havent found anything starting close to 40k€