Commercial Websites

jura-modelisme.fr They offer little choice in materials (profiles, paints, etc.), but are very reactive about new products. It’s not the least expensive, but often interesting promotions.
micro-modele.fr Ex-Train Magique, an online store where one can find spare parts (axles), materials (brass, plastic) and Proxxon tools at the lowest prices. And a very accessible and responsive boss, which doesn’t spoil anything.
apogee-vapeur.ch Artisanal company devoted to the manufacture and sale of very high quality spare parts (wheels, tracks, etc.). The website also offers many uncommon tools, Swiss quality, and reasonably priced.
modellbahnshop-lippe.com My favourite online store in Germany, with prices often lower than in France, especially on German or Austrian brands. The fees are usually very reasonable (e.g. €3.90 since 2017 for an order of more than €100).