Where is a seat of the European Parliament?

EDITORIAL LEARNING AID

Why is this answer correct?

The European Parliament has its official seat in Strasbourg, where the plenary sessions are held. London and Paris are not seats of the parliament, and Berlin is the seat of the German Bundestag.

Parliament: Strasbourg, Brussels, Luxembourg.

This translation and explanation are editorial learning aids. The official German wording and answer key govern the examination.