The heart shaped stamp was issued on Valentine's day, 14th Feb 2012. The “Patch d’Amour” is designed a bit like a tattoo. The stamp is a clear sticker and the background depends on the surface on which it is applied.
I have more of the heart shaped stamps issued by La Poste in my collection of odd shaped stamps. Will do a post on it separately some time soon.
Do feel free to add your thoughts, comments or suggestions
NOTE: Please click on the images for a larger view / closer look.