Hi guys,
Remember Rue Mollien, in Calais, where there is numerous shops. Among them, Chaussexpo:
Clément B. replied:
Yup, and that can be cheaper, but those ones are specifically for hiking. Also selling some socks it seems: http://www.chaussexpo.fr/chaussures-accessoires/chaussettes-collants/chaussettes-noir/258586.html