France's ARS health agency has launched an investigation after hundreds of staff working for Airbus Atlantic fell ill in a mass food poisoning at a Christmas dinner.

The agency said more than 700 people who attended the dinner event showed "clinical signs of vomiting or diarrhea."

ARS did not say what was on the menu at the dinner on December 14 at the company's offices in Montoir-de-Bretagne, near the northwestern city of Nantes.

The workers fell sick over the next two days, according to the agency, but no one was hospitalized.

According to local media, the workers were given a questionnaire to complete online to report their symptoms.

Some workers speculated on social media that the Rocamadour cheese, made from goat milk, may have been to blame. However, no official information on the cause was immediately provided.

The company restaurant was busier than usual that day as staff wanted to enjoy the Christmas-themed meal, local media reported.

Airbus Atlantic is a subsidiary of the European aerospace group Airbus and employs 15,000 people in five countries. The airplane maker employs 134,000 people worldwide.

With material from AFP news agency