 Complete the following phrase:  The most infamous of these mass arrests was the so-called Vel dHiv Roundup Rafle du Vel dHiv which took place in Paris on the 16 and 17 July 1942. The Vélodrome dHiver was a large cycle track situated on the rue Nélaton near the Quai de Grenelle in the 15th arrondissement of Paris. In a vast operation codenamed Spring Breeze Vent printanier, the French police rounded up 13,152 Jews from Paris and its surrounding suburbs. These were mostly adult men and women however approximately 4,000 children were among them. Identifications for the arrests were made easier by the large number of files on Jews complied and held by Vichy authorities since 1940. The French police, headed by René Bousquet, were entirely responsible for this operation and no German soldiers assisted. Pierre Laval, head of Vichy, included the children in the deportations to Auschwitz against general German orders. Most of the deportees sealed in the transports died en route due to lack of food or water. The few survivors were sent to the gas chambers. A few months later, a police operation took place in Marseille, known as the 