A honey bee swarm can be made up of anywhere between 5,000 and 30,000 bees.
If possible try to find a beekeeper to collect them the moment they arrive, waiting until the next day may see them leave and go into someones house where they may be destroyed which is something nobody wants to happen.
More about Bee swarms and Bees in houses can be found on this blog post HERE.
and about Honey bees HERE.
PLEASE NOTE - Only Honey bees form actual swarms as in the photos on this page.
National list for bee keepers in France and Belgium that will collect swarms HERE
I also collect swarms up to about 50km from Civray, 86400 and will try and assist with any other issues you may have with honey bees including colony removal from windows.
Telephone: 05 49 87 65 18
Mobile: 06 34 98 73 92
If you have a swarm of honey bees and you are looking for a beekeeper to collect it you can use the link for bee keepers in Belgium & France and remember to try also looking the Departements adjacent to the one you are in, it may be that there is someone just in the next Departement.