A Paris court held a hearing Wednesday in a class-action effort to hold French health authorities and companies accountable after thousands with the virus died in nursing homes, and families were locked out and left in the dark about what was happening to their isolated loved ones.

The hearing is a first step in likely a years-long legal marathon. Families hope it shines a light on what went wrong last year as the virus devastated France’s oldest generation and deprived their children and grandchildren of a chance to help or even say goodbye.“We want to ensure that mistakes aren’t repeated, that someone is held responsible,” said plaintiff Sabrina Deliry, who has mobilized families around France since her mother’s Paris nursing home was first locked down a year ago.

The hearing Wednesday involves a special measure to demand access to documents or other material involving decisions at nursing homes. It is among many legal efforts around the mismanagement of the pandemic that are working through the French justice system. Others include manslaughter charges, or target top government ministers, but this could be one of the most far-reaching cases.

It targets several nursing homes, the national health agency DGS, the Paris public hospital authority and others. Plaintiffs include family members of nursing home residents, doctors and associations.

Their complaint focuses on multiple issues at French homes for the elderly and disabled during the first half of 2020. Those flaws included mask shortages for residents and staff; testing shortages; the use of a powerful sedative called Rivotril on some residents while homes were locked down; and opaque decisions on which residents received hospital treatment for the virus and which were left to suffer or die in their nursing homes.

The national health agency, the Paris hospital authority and two of the nursing homes named did not respond to requests for comment ahead of the hearing.

After France recorded Europe’s first virus infections and deaths a year ago, French officials shut down nursing homes to outsiders and kept residents inside. The government said it had to act fast to protect the country’s most vulnerable populations. But many families say the lockdown deprived them of decision-making abilities for their loved ones, and that in some cases the enforced isolation worsened cognitive and other health problems.

Recognizing these concerns, President Emmanuel Macron relaxed some rules for nursing homes ahead of everything else as France’s first lockdown eased. But for many, the damage had already been done. And new waves of infections in the summer, fall and winter sent many nursing homes back into temporary, repeated shutdowns.

Official figures show that nearly 25,000 people with the virus have died in French nursing homes out of more than 87,000 lives lost nationwide – a death toll still climbing by hundreds every day. But thousands of other French nursing home residents who contracted COVID-19 died after being hospitalized, and studies suggest they make up as many as half of France’s overall virus victims. That is among the highest proportions worldwide.

French officials say mask shortages at the outset of the pandemic were beyond their control and a global problem and note that masks have been mandatory and widely available since last summer. Nursing home directors have defended their decisions to lock out visitors given the vulnerabilities of their residents.

Dr. Alain Masclet, head of group AR2S involved in the lawsuit, said the court process “will allow us to define what was forgotten, the shortages, the failures.”

The goal, he said, should be to ensure: “Never again.”