I bought a set of Triplinox by Letang Remy in 1992. I have the same problem (delaminating).
They were sold saying lifetime warranty (but I do not have any written proof of it), but also saying that they were <<Guy Degrenne>>.
The company is Guy Degrenne Letang Remy, mostly known as Guy Degrenne, and I am waiting for them to examine the set.
the current adress is
ETS GUY DEGRENNE - BP 50056 - Route d'Aunay - 14502 VIRE.
but I believe that you can leave your cookware at any (good) Guy Degrenne store (which I am now doing in Montpellier).