This was a common and accepted practice and many artists were involved. The result being that today it is often hard to attribute a rug with a specific artist as they have often lost or never had their label, signature, monogram, invoice or certificate. This makes it extremely difficult and time consuming to trace the origin of the rug.
I call these types of rug 'Faux Amis' (False Friends). The rugs belonging to this group are not copies, but are original pieces in which elements of the composition, the colours, or the patterns are borrowed, or recall the style of another designer.
Sometimes you are able to find documentation that will help to identify the rug. That is the case with the small black and white advertisement illustrated below.
However, the advertisement shown here attributes the rug to Paul Follot and states that it was produced by Tapis France-Orient in the Zaret workshop, in the suburbs of Paris. It also states that the carpet was exhibited at the 1937 International Show and made for the office of the U.C.A.F chairman. The advertisement was published in an issue of Decor d'Aujourd'hui magazine of 1937 (No. 24) and also in two issues from 1938 (No. 27 and 28).
However, in this period Paul Follot was no longer working for Pomone of the Bon Marche and had lost much of his influence due to the creation of the U.A.M association, which had sponsored a completely new direction for the decorative arts since the beginning of the 1930s. The manufacturer mentioned in the advertisement is almost unknown.
From this, you can perhaps understand why a carpet documentalist's profession can drive them crazy ... sometimes.