Bonjour !!
Repairing an inlaid nib seems to be difficult. I have more or less a similar problem with my PFM V.
Replacement of the nib or the nib assembly is the most common way to deal with damaged PFM nibs (so I am told) You could try penhome in UK
See this pic taken from their site
I do not know if they want to sell you a spare nib or nib assembly....
You could also buy a donor pen.
I also know from at least 1 source that there is some development going on to retip a PFM nib. And that sounds interesting, but no matured solution yet (as far as I am informed).
If you find a way, please inform me
bon chance
Ruud