D'Hondt, I guess you mean, is not a method to introduce distortion of representation, but precisely a method _to reduce distortion_ in parliamentary systems with imperfect representation to begin with (i.e. with circumscriptions). The distortion is primarily coming from something else other than d'Hondt, e.g. electoral circumscriptions being too large or too small.
> taking into account that independentist parties are forbidden in Portugal or France and that here they not only are allowed
This is not true at all. Search for corsican auto-determination. France actually has even allowed auto-determination referenda for DOMs in the very recent past. Certainly it's not exactly the same and I'm oversimplifying (many simply want to get rid of these regions), but please stop pointing fingers to France; you may realize we are not as different from Spain as you think.
> taking into account that independentist parties are forbidden in Portugal or France and that here they not only are allowed
This is not true at all. Search for corsican auto-determination. France actually has even allowed auto-determination referenda for DOMs in the very recent past. Certainly it's not exactly the same and I'm oversimplifying (many simply want to get rid of these regions), but please stop pointing fingers to France; you may realize we are not as different from Spain as you think.