Thank you all for your answers. You are all agree about the importance of the fire management.
@Frosty, I will have a look to "the art of blacksmithing" book for such systems.
@George, thank you. I'm from France, North West, Brittany. I'm going to edit my profile.
I'm thinking to start with solid fuel because it seems that here in France, nowadays, it's cheaper and also more simple to begin blacksmith, according to some french smith on youtube. But as I said, i'm not even a beginnner for the moment so I have to see by myself.
And at first sight, i am more attracted to the old blacksmith techniques. There is something primitive in it that appeal me. A man and a fire..!