They haven't just "made it easier to fire people". They wrote a law that basically when used in coordination with another contestable law passed nearly a year ago (loi macron) allows them to :
Bypass minimal wage. They (the employer union whichi wrote that law) want to pay people 800€/month instead of the legal minimum of 1200€.
Bypass weekly maximum hours (They want you to work 60h in your contract for that same pay ? They can !)
(cut out) Unpaid additional hours in unlimited number (contract say 45h for that pay and they declare you have to stay 60h and no money for those hours or be fired a few months after you signed it ? They can !)
(cut out) Bypass maximum hours rule on a shift (ie they wanted you to work 20h in a row ? They can !)
(cut out) removed recovery time after long shifts (they want you to show up back 4h after that 20h shift ? They can !)
Make people work 6 or even 7 days a week (they want to ask you 10h more a sunday after a monday-sunday 10h/day shift ? they can !)
(cut out) tried to make people loose a week of leave a year (you have 2.5d of paid leave per month, and unpaid leave DO NOT exist in france. You don't show up when asked you're considered a frauder by your boss and generally end up fired)
(cutout) Make teenagers work, sometime for free, most of the time below minimal wage as an "apprenticeship"
(cut out) backed unpaid intership practice. It's like work, it's in fact work, but you don't have any salary. Lots of companies used to do that : ask you to take a year of unpaid internship before they would "decide" whether to hire you or not (spoilers : they never hire and just take another unpaid intern instead of course). Now we passed a law making it illegal not to pay people after 3 months of internships; and those assholes found a loophole saying they didn't have to respect minimal wage anyways since it wasn't officially work, good luck living on a 200€/month "gratification" of course.
(cut out)
Tells you everything you need to know about that law.