While all the honey fell within the EU’s allowable limits for safe consumption, honey from hives downwind of the Notre Dame fire had average lead concentrations up to four times that of samples collected in the suburbs or countryside surrounding the city, and up to three and a half times the amount found in Parisian honey pre-dating the fire.
Because honey bees forage within a two- to three-kilometer radius of their hive, honey can provide a useful localized snapshot of the environment. As the bees forage, they collect dust and airborne particles, which make their way into the honey.
https://www.eurekalert.org/pub_releases/2020-07/uobc-lri072820.php