It was at night from
10 to 11 September 2000 near Paris.
About 0:55 local time Prince Guillaume and Prince Sibilla of Luxembourg had a car accident at the motorway A10 close to Briis-sous-Forges near Paris, France. Two other cars were involved in the accident. Prince Guillaume was taken to the Hospital Henri-Mondor in Créteil. His condition is said to be critical. He has a fracture of the skull and is in a coma. Princess Sibilla was brought to the hospital in Evry with a broken leg. Grand Duke Jean and his wife Joséphine-Charlotte immediately travelled to France after hearing about the accident.
http://www.nettyroyal.nl/newssep00.html Here is a photo of their car - terrible.
http://www.gouvernement.lu/salle_pre...uil/index.html