Ciao Andrea !

I'll try to explain you in english, so if someone has something to add ...

The things did you called "flaps" are the ailerons, and it's normal they are one up and one down...that means the plane is rolling on the direction of the lowered aileron.
The tail elevators are both down 'cause the Hanriot is diving.
The move in the pic looks like technically correct, he probably is diving and rolling to swiftly slide on the enmy tail.