I could be interested in just the sliding door one (very smart!), depending on the cost of shipping to France...
My experience of my DIY solutions, for what it's worth:
I fitted 3 mats using self-adhesive Velcro tape.
The front mats were a nuisance, mainly due to rotation of the foot while climbing in & out. We eventually removed them.
The rear mat has proved very useful at reducing dirt ingress & we also often sit on it, either just to admire the scenery or to eat off the removable table which is about the right height.
Your one looks smarter & more comfortable!
The self-adhesive Velcro did not stand up to the temperatures when the van was parked in the sun, and ended as a very sticky mess.
I understand that "industrial-grade" Velcro may be available & would stand probable temperatures, but I haven't found it yet.
If I was selling mats (I'm not) I might consider offering them separately & offering high-temperature Velcro pads.