I have been offered a post-doc position in France (I am not from Europe). However, I came to know that post-doc salaries in France are regulated. In view of this, can anyone inform what kind of benefits one can request/expect along with the usual salary for a post-doctoral position in France ?
Postdoc salaries are not always regulated, it depends on what research organisation your lab falls under. The big players include CNRS (has regulated salaries), CEA (which does not), and others.
If you have a postdoctoral position, your salary will be pre-determined by your lab or by the supervisor who has the funding to pay you. If you have a postdoctoral fellowship from outside France, it's possible that your lab would regulate the salary (e.g. from a wider European fellowship) to match their salary scale (possibly pocketing the rest for CNRS, if it's a CNRS lab). This can be a rather large amount, as evidenced on a rather unfortunate post on academiaSE. But that depends on which umbrella you fall under, in the first paragraph, and if you have a fellowship, talk to your funding body to figure out what the case will be for you. In whatever circumstance, I would make sure to define this with the lab before accepting and moving.
Benefits are the same for everybody - you will be able to take part in the national healthcare scheme, although it will take several months before your healthcare card (carte vitale) arrives. The social health insurance covers roughly half the costs of most common treatments. For example, it's usually 27 euros to see a GP, and a little under half of that is reimbursed. Whether you decide to take supplemental health insurance (a mutuelle) is up to you.
You will, in general, have a very generous number of holidays. I believe for PhD students it's 9 weeks, and I think it's the same for postdocs. Holidays are paid by default. As far as I know, postdoc/PhD holiday time is paid time. CNRS permanent staff get their holiday time 'paid back' to them if they don't take it. I don't have the specifics about what pay they actually get for not taking their full allotment of holiday time. People don't usually take that much. I know I certainly haven't in a French PhD.
Most academics will take a few weeks of holidays every summer, and a couple of weeks around Christmas. You also get the major French holidays, including those which fall on a Thursday, where people usually take the following Friday off ('the bridge').
You will be reimbursed for work-related travel within and outside of France. In CNRS labs, you usually don't pay to book a hotel within France. CNRS or your project funding will pay for flights or train tickets for work-related travel. You will need to pay international hotel costs for work-related trips yourself, and will be reimbursed some time later.
Unless you're in an uncommon circumstance (i.e. I've never heard of this happening for anyone) you won't have your moving expenses reimbursed.
You should probably be aware that salaries in France are comparatively low with respect to the US, UK, and other 'big players' in academia. That combined with my first point makes it difficult to recruit talent from outside France, unfortunately. But other aspects make quality of life pretty nice, healthcare especially.
If there's anything else you want to know about, let me know and I can try to answer. I'm a late PhD student in a French lab (non-EU citizen, so I know the visa struggle well), and I'm surrounded by postdocs I can ask questions to.
You might also want to consider that doing administrative things (visa, bank accounts, renting a flat) can be very difficult when you don't speak French. Not impossible, but not easy either!