Who sells foam rubber as used in mattresses

Does anyone know who sells foam rubber? In the Brest / Morlaix / Carhaix area?

I’m trying to fit -out a VW Caddie van as a campervan. The width I need is wider than a single bed mattress but not as wide as a double bed.

Just the foam cut to size without fabric cover would be ideal.

There is a shop in our big town that sells it, look for a tapisserie near you, but prob easy via internet