What is a good starter mountin bike? (in France) I have been riding a road bike for the past year. And now, I want to see if mountain biking is for me or not.

Ideally, it would be a bike that could handle a lot of climbs and be reliable for less than 700€.

I live in France if that helps reduce the number of brands/models available.
I want to see if mountain biking is for me or not.
  Ideally, it would be a bike that could handle a lot of climbs and be reliable for less than 700€  


I can't recommend products but I can offer some thoughts on buying a new bike.  

Most major bike makers have a model (usually more than one) in your price range. The brands keep an eye on each other and usually stay pretty even on features and quality at a given price point. Given the variety of mountain bikes - even from just one manufacturer how do you choose between the styles?

On any bike it comes down to your preferences. In order to know what your preferences are you have to try different things and see what works for you. That's why the ice cream store offers little samples - so you can try it and figure out what you like.

The key is time in the saddle on different bikes.
It would be nice if you could gain experience as cheap as possible.

There are many ways to find the right bike. Here are a few options (in no particular order) 

Option 1:
Find someplace that rents a variety of mountain bikes. 
- Hard tail
- full suspension
- etc.   

Ride a bike enough that you have a feel for what it does and then try a different bike. Figure out what you like and then buy something new.

Option 2:
Borrow a mountain bike from someone who likes you enough to loan you their bike.

Option 3:
If you are careful it is possible to buy a used bike, ride it and then sell it for most of what you paid for it. This can be a lot of work and it takes some knowledge of bikes and the bike market but some people really like wheeling and dealing.

Option 4:
Bike shops will let you test ride bikes and talk with you about what you like and don't like. It's not the same as a day on the trail with a rental bike but it is cheaper.

Once you decide if you like mountain biking and learn what you want in a bike you'll be able to make an informed purchase.

Last thing. How a bicycle is assembled matters.
There is a right way and a wrong way to assemble a bike. In the best case a poorly assembled bike is annoying. In the worst case it's dangerous. Anything you buy should be assembled by someone who knows what they are doing.