Is it wasps or bees?
Bees are usually less aggressive and have a more “hairy” body. Wasps are slimmer and more often circle around food and drinks. If it is a swarm of bees, it is worth contacting a beekeeper.
What not to do
Do not spray the nest with random aerosols and do not try to knock it down. This is the easiest way to trigger an attack by many insects at once.
Do not block the entrance by force — wasps may find another exit (even into the interior of the building).
Safe steps until professionals arrive
Keep your distance, secure the area (children/pets), close windows near the nest. If possible, limit attractants: sweet drinks, fruit, open bins.
If anyone is allergic to venom, do not delay — a single sting can be dangerous.