Article 4: denied boarding
When the airline bumps you — usually from overbooking — Art. 4 gives you compensation, a refund or re-routing, and care.
Denied boarding happens when an airline refuses to let you onto a flight you hold a confirmed booking for, checked in on time and did nothing wrong — almost always because the flight is overbooked.
What you are owed
The airline must first ask for volunteers to give up their seats in exchange for agreed benefits. If you are bumped involuntarily, you are owed the same fixed compensation as for a cancellation (€250/€400/€600 by distance), plus a choice of refund or re-routing under Art. 8, plus care under Art. 9.
Unlike delay or cancellation compensation, denied-boarding compensation is not reduced by "extraordinary circumstances" — overbooking is the airline’s own commercial decision.