The European Parliament on Tuesday cancelled plans to hold a plenary session in Strasbourg next week after the French city was placed in a coronavirus "red zone".
"While we are very disappointed about this decision, we have to consider that the transfer of the administration of the European Parliament would entail quarantine for all staff upon their return to Brussels," said the speaker, David Sassoli.
The European Parliament has two bases, with the bulk of its work being carried out in Brussels alongside the other institutions of the European Union, and regular week-long sessions in Strasbourg.
The costly and time-consuming trek for MEPs and their staff between the two cities has often been criticised but France insists on its right -- enshrined in the EU treaty -- to host the assembly.
But France also faces a surge in new coronavirus infections and on Sunday added seven more regions to its red zone, covering the eastern cities of Lille, Strasbourg, and Dijon.
"The European Parliament's wish is to return to Strasbourg and we are confident that, in the face of a decline of the pandemic, this will be possible," Sassoli said.
"The plenary session of the European Parliament from 14 to 17 September will take place in Brussels."