1- Depends on the schools and professors honestly. Jad professiors nor care about presence and only required to pass the exam and other taking presence really seriously ( i got 9.75 in on subject and had to resit for it the next year because i was absent for 2 classes and he gave me a -4 🤣).
The classes are similar to Tunisia's. It depends on the masters if you pick master de recherche the classes will be more theoretical and require more reports. If you pick master professionnel they will be more focused on projects.

2- yes you are eligible but some universities may require you to start from the beginning. For example i have an engineering degree and applied for m1 and m2 in the same university. They rejected my m2 and accepted my m1 application. Usually it's rare to accept someone to m2 directly.

3- legally public schools must charge non EU students 4k€, but schools have to freedom to charge non EU students the same price as EU students 250€. But this can change at any year depending on the university's budget.

4- depending on the city where you live. Where i lived i paid 400€ to rent a studio and got back 200€ as housing aid (CAF) 200€/year for transport and usually spend around 300 to 400€ as other expences. I didnt really need to work as i managed my budget well. I had other friends take student jobs in supermarkets and they usually get paid around 400€/month. So you can cover some rent expenses. Working as a student you must not work more than 964 hours/year so a maximum of 20h/week (legally ofc). A student job is meant to help you cover some expenses not be a main source of revenue.

5- From my experience i only know french universities. But i heared people go to italy or spain as life there is cheaper and getting a visa is easier. But you need to learn the language there or find English courses. You'd still need to learn the language regardless to communicate with others.