Just purchased a French 20 Francs gold coin from the 1830s, July Monarchy. I am now only 1 coin away from having a complete set.

Here’s the first of them:

https://www.vcoins.com/en/stores/numiscorner/239/product/france_napoleon_i_20_francs_an_12_paris_vf3035_gold_km651/923051/Default.aspx

“An 12” means 1803, year 12 of the Revolutionary Calendar, one aspect of the metric system that was abandoned.

The $350 price listed there is old price, an An 12 is worth more like $430+ depending on condition.