Since it is a boulevard and not a highway, priorité à droite applies here, giving right-of-way to the driver entering the boulevard from the righthand side. When driving up to the intersections/on-ramp you will see the sign for this -- white triangle, outlined in red, with an X in the middle. For example here on googlemaps. It comes from an era when there were many intersections without signs or signals, so there had to be a system of it, and priorité à droite was what they devised in France.