‘PF’ stamp - the French Importer’s hallmark for Pelikan on nib of Pelikan M800.jpeg

This ‘PF’ mark is the hallmark for Pelikan pens.
It is on the 18k gold nib of my ‘W.-Germany’ M800. The nib has a French ‘Eagle-head’ mark to confirm that (a representative sample of) this nib has passed the French assay for 18k gold.
 

The fact that it is enclosed within an oval shows, according to French law, that it is a ‘responsibility mark’ for an Importer.

A ‘responsibility mark’ for a manufacturer of an item would, according to French law, be enclosed within a losange - a diamond, or straight-sided polygon

(See e.g. my photo of the mark on the nib of my 1984 Parker 75, on which the losange is the shape of the frontal elevation of a house with a pitched roof.)

For details of the relevant French law on Customs/Assay hallmarks, see:

https://www.douane.gouv.fr/fiche/regles-de-marque-pour-la-garantie-des-metaux-precieux