I bought a Negronne & a Celeste this spring , it was a vicious grower until it started producing some fruits, I guess it gives all the energy to produce those fruits.
what would you do in my place, would you cut all the figs off the tree and let it focus its energy on growth? or just let it be?

My Celeste actually is not growing and the figs on it are are having a hard time growingas well

You're greedy. ;-)) You want 40 figs and growth from a small plant? Give the plant a break already.

It depends on what you want out of the tree. If you are trying to grow a large tree quickly to plant in the ground as a cold hardy tree, I would cut all but 1 or two off. But if the tree is to remain in a container, then slow growth with a lot of figs sounds ideal and I would leave them all on there. Cutting half off wouldn't really achieve either result in my opinion. As far as the Celeste goes, the figs remain fairly small, and them the ripening occurs all in a three or four day period when they suddenly swell and change color, so I don't think the tree is struggling. If it were it would begin dropping the figs...

Fertilize it and wait a week.  If it still isn't producing tiny new leaves take 40% off.

Miracle grow gives quick results.  Since your plants are in pots use the small scoop - read the directions.  I know at least 1 person who killed his plants by using too much (the big scoop).

Been useing the big scoop for many years per gallon of water 24.8.16 formula, economy size Mg box @ 18.99

Shh dont tell anyone.