Opening of the blades
Counterclockwise left view of pergola
The blades will rotate counterclockwise when standing outside the pergola and looking at the left side.
So if the facade of your building is at the back, your slats open from front to back.
With the 45° slats, the sun's rays will be able to pass through mid-season and thus enter your home if your pergola faces south, and if your slats are parallel to the facade.
This orientation is ideal for pergolas located in regions north of Lyon, where solar gain in winter is necessary/desired to warm your main room.