What the limiting valve does really depends on it's initial design parameters.
Given that the car in question has equal diameter rotors with 38mm front caliper pistons and 32mm in the rear, even without the limiting valve in place, the rears can only ever apply 70% of the force that the front ones do in a single circuit system.
I don't know the specs or indeed the exact design of the Renault valve, but I assume it is a regular 2 piston proportioning valve?
For discussion's sake, say it has a 400 psi line pressure trip point, up to that point the rear brakes will be working at their maximum potential relative to the front brakes (70%).
The diameter of the valve's pistons are unknown (in this thread anyway) but let's say there is a 50% difference in surface area. So the valve trips at 400 psi, the brakes get applied harder and the main line pressure rises to 800 psi so the valve will now transfer 400 psi plus 50% of the extra main line pressure to the rear, so at 800psi of main line pressure, the rears would be receiving 600 psi of pressure via the valve. At 1200 psi of main line pressure, the rears would receive 800 psi of pressure.
So you can see there is a curve where the the rear line pressure (relative to the front) falls away (as percentage of the front) as the main line pressure rises, which makes sense, as the higher the main line pressure, obviously the more the weight of the car is transferring forward under brakes.
Again I'm assuming the Renault has a two piston proportioning valve, as fitting anything else really wouldn't make sense?

So Fireblade is sort of correct in that the rear brakes should be working at their maximum potential (70%) up to the point where the limiting valve begins to take effect, and at that point the overall braking effort is gradually transferred, (at a predetermined rate by the limiting valve) to the front brakes.
One would have to think if rear pads are not wearing at all (with the limiting valve in place) that the valve itself is faulty?
Of course the Renault's braking was set up to work at its best ex factory, so once one relative element changes the whole thing is mucked up.
Even using different pad material front to rear will upset the effects of that predetermined brake balance.