They are among France's darkest days: Police dragged over 13,000 Jews from their homes, confined them in a Paris cycling stadium with little food or water, and then deported them to their deaths in the concentration camp at Auschwitz. But even in France, one of the most brazen collaborations between authorities and the Nazis during World War II is unknown to many in the younger generation.

Police are hoping to change that, opening up their archives on France's biggest single deportation of French Jews for the first time to the public on Thursday.

The often chilling records are being exhibited in the Paris Jewish district's city hall to coincide with the 70th anniversary of the two-day "Vel d'Hiv" roundup, named for the Velodrome d'Hiver, or Winter Velodrome. Many thousands were rounded up on July 16 and 17, 1942, then holed up in miserable conditions in the stadium, just a stone's throw from the Eiffel Tower, before being bused to the French camp at Drancy and then taken by train to Auschwitz.

Tallies list the daily count of men, women and children detained, alongside stark black and white photographs of deportees. A registry of those forced to wear the yellow star and a Jewish census show how police knew who to take. Meticulous handwritten lists detail personal possessions handed over to police. Others list the value of property, such as jewelry, confiscated — often forcibly — during the deportation.

France struggled for years to come to terms with the extent of its wartime collaboration with the Nazis, but over the decades officials have been showing greater willingness to acknowledge the shameful period in its history.

"This is our history, it's vital for the country to know," said curator Olivier Accarie. "Today, we are ready to confront this."

Some police helped

The administrative indifference of the documents is striking.

On July 17, Mrs. I. Rosenbaum signed that she had given up over 1,450 francs worth of possessions before being deported. But there is a further hand annotation: She tried to conceal 50 British pounds that were confiscated.

One page records the pre-dawn start of the roundup, but in one of the archives' only rays of hope it reveals that not everything went according to police plan: "The operation against the Jews began this morning at 4 a.m. (But) it has been slowed down. … Many men left their homes yesterday." Though experts say the original plan was to deport 27,000 Jews from Paris, some 14,000 managed to avoid roundup or escape.

"Even some police helped them get away," said Charles Tremil, president of the History and Memory Association, a group that raises awareness about Jewish children deported from Paris' 3rd district.

One particularly chilling document, disturbing in its matter-of-fact tone, is dated July 22, the day when the last of the deportees were taken from the velodrome, noting that the site will soon be operational again for use.

"The Jews interned at the Vel d'Hiv were directed this morning … to the camps," it reads. "In around one hour, the Winter Velodrome will be available."

The exhibit is one of a handful of ways the country is remembering the deportation. On Sunday, French President Francois Hollande is to give a speech at the old velodrome site, the first time such a commemoration has been made since former French leader Jacques Chirac led a ceremony there in 1995 and acknowledged the state's role in Jewish persecution.

On Monday, a minute's silence was held at the Drancy camp by war veterans and survivors to remember the victims. Eighty-six-year-old holocaust survivor Yvette Levy — who was deported from the camp — came to remember those who lost their lives.

"With a lot of emotion, I think about the lives that were broken … whose only misfortune was to be Jewish," she said. Levy added, with anger: "(They say) we should forget, we should forgive. It's not possible."