Thanks smitty but it's not the paintball marker, it looks identical to the real handung. Here's the story behind my question:
My mate bought such gun from a friend of his friend, it's supposed to be non lethal handgun, looks the same but can't kill. I looked for informations on my language about it on the internet and there are very few about this type of handguns, but one of the only things about its function was that it can be used as a tear gas. The thing is that the handgun looks identical to Browning hi power series, model GP DA 9, the only different thing is that it has a little 's' after 'DA' instead of number '9'. I'm starting to wonder myself if that is a real handgun, but I wonder why would somebody sell it by a different name, if you get what I mean. It all seems to be pretty fishy to me, so I want to look up informations on english language but don't know the name for that type of handguns. If you want I can post some pictures for you. Thanks.

I found some info on one of the site's. I'll try to translate it as good as I can.

''This type of handguns(includes revolvers too) are very similar to real handguns by its construction but main thing in which they differ is that they shoot gas instead of projectile. So they have different barrel and different caliber so you can't shoot real bullets from them.

Bullets have plastic, paper or some other kind of sealing(some kind of cap that hold the material in) at top of it, instead of the real projectile and under that there are some crystals which when heated develop into CN or CS gas and go out of the pistol. There are also blanks that are used for signalisation or  simulation in the movies for example.

Minimal shooting distance is 1-2 m, and depends of the caliber. Shooting from a too close range, because of the unignited crystals and gases, can be pretty dangerous. Range of the gas cloud it creates is from 3 to 7 meters and also depends of the caliber''

No rush anymore, it's all checked and everything is just as it should be. No more doubts, this is not a real handgun for sure. This type of handguns is totally legal to carry without permission as a self-defense weapons.