Pocket watch charm France

Pocket watch from Pierre Lanier that can be a charm from France and vintage. 1st gift from first boyfriend over 40 years ago. Not sure how to open and if can to replace battery? This is made with dried flowers and is a scene of 2 love birds on a tree branch. Super amazing art work. Zoom in. Use as a charm on your favorite necklace or just as a cool collector’s item from France.