--import-bookmarks option

[robin5wood gmx com]

Hello,

I am trying to import bookmarks using the command line option :
epiphany --import-bookmarks=bookmarks.rdf

No bookmarks are imported from the file.
The bookmark file seems to be good because I can manually import it using
the bookmark manager.

Is there a special way to use --import-bookmarks option?

I am using epiphany v3.0.4 (debian package)

Thank you very much for any help.
Robin