France Stamps Franc Currency

I bought a big collection of French stamps with Franc vlaue (Before euro)
when I sell it, can I mention that I can be used for postage? or we can't use Franc for postage anymore? all should be recent euro stamps?
Thanks

Hi itcontact, welcome.

I assume you are in France to ask such a question as you could not use France stamps in any other country than France.

From La Poste in France (French Post Office)
http://timbres.laposte.fr/faq.jgi?siteLanguage=en

ARE MY STAMPS IN FRANCS STILL VALID?

Stamps in francs have retained their postage validity provided that their face value is converted into euros and extra postage is added to bring the value up to the new price. Please refer to current prices.

CAN I USE STAMPS MARKED "France 20g" WITH EXTRA POSTAGE AND USE THEM TO SEND ITEMS ABROAD ?

Yes, stamps with no face value may be used in the same way as any other stamp. However, care must be taken to ensure that the total postage conforms to the price of the destination zone. Furthermore, stamps with no face value automatically assume the new value following a price change. Please refer to current prices.

But I tried to search La Poste and because I do not understand French to the extent that is needed to intelligently navigate around on the site I got lost.

I do not know the current prices. I do not know what the exchange rate is for changing Francs and centimes into Euros.

Thanks So much for the reply