New restrictions are coming in France as the nation deals with the highest increase of COVID-19 cases in Europe since May.

French Health Minister Olivier Véran announced a set of targeted restrictions Wednesday to be implemented in various cities for two weeks.

Starting Saturday, in Paris and seven other major cities, parties will be prohibited, with outdoor gatherings limited to 10 people.

Bars must shut their doors at 10 p.m., gyms will be closed and sporting events will be limited to 1,000 spectators.

Meanwhile, Marseille and Guadeloupe are enacting stricter rules; starting Monday all bars and restaurants will be closed.

French officials reported 13,072 new cases on Wednesday, just short of the highest daily record of 13,215. France now has over 481,000 COVID-19 cases and at least 31,459 fatalities.

ABC News' Ibtissem Guenfoud and Christine Theodorou contributed to this report.

Dr. Blythe Adamson, a former member of the White House coronavirus task force, told "GMA3" on Wednesday, "One of things that we just learned recently -- and published in a new study today in Clinical and Infectious Diseases -- is that being indoors, you're 20 times more likely to catch COVID from an infectious person than if you were around them outdoors."

Adamson is now adviser to Testing for America, a nonprofit established to help solve the testing crisis.

Adamson stressed that the U.S. must "be flexible and adapt, so as we learn more about the science, we're willing to change our public policies so that they match the best science."

"There's a lot of work for us to continue to do over the next couple of months. As we move forward into flu season, it's even more important that we're able to distinguish between a viral infection that's from influenza or coronavirus," she said.

While testifying at a Senate hearing Wednesday, Robert Redfield stood by his timeline on when most Americans would be vaccinated. He said the expectation is that millions of doses will be ready by April and that it could take until summer 2021 to get the vaccine to most Americans.

“I think that’s going to take us to April, May, June, possibly July to get the entire American public completely vaccinated," said Redfield, director of the CDC.

When Dr. Anthony Fauci testified he said that about 50 million doses of all the viable vaccine candidates will be available in November, and more in December, and that those doses will be prioritized to health care providers and vulnerable populations.

ABC News' Stephanie Ebbs contributed to this report.

At a Senate hearing on COVID-19, Dr. Anthony Fauci on Wednesday addressed some lesser-publicized side effects seen among some COVID-19 "long-haulers": heart inflammation and cognitive abnormalities.

"A disturbing number of individuals" who have recovered from COVID-19 and "apparently are asymptomatic," "when they have sensitive imaging technologies such as magnetic resonance imaging or MRI," they're found to "have inflammation of the heart," Fauci said.

Fauci also said a symptom among COVID-19 "long-haulers" is "cognitive abnormalities," like the inability to concentrate.

"These are the kinds of things that tell us we must be humbled that we do not completely understand the nature of this illness,” stressed Fauci, director of the National Institute of Allergy and Infectious Diseases.

Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), also testified Wednesday, noting that young people -- 18 to 25 year olds -- are making up 26% of new infections.

ABC News' Anne Flaherty contributed to this report.