>are there words
> > from French substratum which are to find in the substratum
> > of Spanish or Rom. for example?
Actually substrate influence is, more often than not, just assumed in the
Romance languages - it is rather difficult to find clear examples of how a
substrate language has influenced the Romance dialect which emerged. Many
of the arguments work backwards - since French (or Spanish or whatever) has
this feature or word, and other Romance languages don't, then it must be
substrate. It is much easier to see variations in Romance languages as
layers of history, with innovations spreading from Italy; Sardinian
relatively isolated from the innovations, Romanian separated from them in
the 3rd century, and the others more in touch with them for a bit, before
losing contact.
So this discussion of substrate may be an over-concentration on just one
issue, when there are others at play as well.