Saad al Hilli and his wife Ikbal, from Claygate in Surrey, and her mother Suhaila al Allaf, who lived in Sweden, were all fatally shot on a remote forest road in Chevaline near Annecy on September 5, 2012. Local cyclist Sylvain Mollier was also murdered.
French police yesterday arrested a 48-year-old man, from the Haute-Savoie region of France, in connection with the killings.
According to local media, the man is a former municipal policeman who lived close to the scene of the murders in Chevaline.
Investigators were said to be looking into places that he had frequented.
Annecy prosecutor Eric Maillaud said the arrest followed the release in November of an artist's impression of a motorcyclist seen near the scene of the murders.
In a statement, he said: "A 48-year-old man living in Haute-Savoie was brought in for questioning by Chambery police this morning.
"In the interests of the importance of presuming innocence and in the absence of a direct link between this man and those involved in the incident, no further information about his identity will be given."
Surrey Police said the arrest came from a line of inquiry in France and not as a result of the investigation carried out in the UK.