It was part of the whimsy of Robert Coudray, the Poètes Ferrailleur in the title. A ferrailleur is a scrap iron merchant but Coudray has turned the scrap iron into whirling motion (this one wind powered), and to works of imagination, he is the iron poet.
Perhaps this sail plane is about to take off
the boat-car set sail
The entrance looks as though it is about to be towed into the air. Inside there are automata, a mechanical theatre of fey creatures, rolling balls and lots of kinetic energy. I didn't take any photos inside, how could they capture the motion, so here is a short taste.
