Can I stay more than 90 in 180 days for medical reasons?

Is there a way for a foreign visitor to extend a visit to France beyond the 90-day limit? My wife had an accident and requires regular medical follow-ups.

If you are a non-EU citizen with a 90-day visa waiver, it is possible to apply to the local prefecture for an autorisation provisoire de séjour (provisional right to stay) on compassionate grounds. 

This would avoid your stay becoming illegal, with potential complications such as a fine at the border when leaving. The Dordogne prefecture said the authorisation cannot exceed 180 days.

It stated that the documents required include your passport and a copy of it, proof of health insurance (such as an Ehic or Ghic card), a copy of a return travel ticket out of France and a doctor’s certificate. 

If you are staying with someone, you will need a declaration from your host as to their relationship with you and willingness to take financial responsibility for you where required. 

Other reasons for asking for such an extension could be work-related, such as a training course being prolonged or a delay in the execution of a contract, or other ‘exceptional and unpredictable’ events.