Benjamin Orset died of food poisoning on 22 January, the day after eating in Quick.
The Avignon prosecution opened an enquiry on 18 February and pointed out serious lapses in hygiene standards.
Staphylococcus bacteria was found in Orset’s gastric juices as well on five of the eight employees present on the evening in question and on the tiled floor of the food wrapping stand.
Quick has broken off its contract with the manager of its three restaurants in Vaucluse.
The restaurant was closed by prefectural order on 22 January. It reopened on 11 February but closed again the following day for building works.