You can find a french geologic definition of plateu at this site. I guess the term is equivalent to plateau on US reference bibliography, but there migth be some little differences.

To shortly answer your question about how was it formed, the Ruisseau du Bondon excavated the plateau, forming the slopes and the valley.

To deeply answer a reference to a local geomorphologic study would be needed. There should be some study on geomorphology journals, as the zone looks interesting. If you are at University you could make a research for "Plateau de Vitrolles" and you migth find a complet explanation from local geologists.

This French page refers to it as a cuesta; this is plausible, but the strata underlying cuestas usually slope more than what appears in your picture.

(generalized cuesta image from Wikipedia)

"Plateau" is also plausible, but this is not very specific. The landform in your picture doesn't have quite the extent of the Colorado Plateau.

Tableland or table is probably the most generic name for the entire regional structure under the rock layer.

If you are talking about the remnant under the pin in your image (and especially if this were in America), then we'd have no trouble calling it a mesa or even a butte.

(Wikipedia image of a mesa in Monument Valley)