Paris, Sep 30 (IANS): A massive boom heard across Paris on Wednesday morning briefly caused panic as residents reported buildings shaking and windows rattling.

Police in the French capital quickly confirmed that the noise was made by a fighter jet breaking the sound barrier, and asked people to stop calling the emergency line, as per media reports.

"A Rafale (warplane) based at Saint-Dizier, intervening to assist an airliner which had lost contact, was allowed to break the sound barrier to join the airplane in trouble. It broke the sound barrier east of Paris," Army spokesman Colonel Stephane Spet said in a statement.

It was not immediately clear whether the problem with the commercial jet had been resolved.

In a city already tensed since a knife attack outside the former offices of satirical magazine Charlie Hebdo on Friday, the unusually loud blast sent people onto their balconies to see what had caused it. It also prompted intense messaging on social media and a flood of calls to emergency services.

The Paris police prefecture explained what had happened in a statement on Twitter and urged people not to call emergency services about the noise.