From an AP Explainer:

Paper ballots tucked in paper envelopes. No absentee voting, and no early voting either. French voters in Sunday’s presidential election are using and old-school system that has defied calls for more flexibility or modernization….

HOW DO THEY CAST BALLOTS?

Voters make their choices in a booth, with the curtains closed, then place their ballot in an envelope that is then put into a transparent ballot box. They must show photo identification and sign a document, next to their name, to complete the process.

Machine-voting has been allowed on an experimental basis, but the purchase of new machines has been frozen since 2008 due to security concerns. Only about 60 towns still use them, out of 35,000 municipalities in France.

A nationwide effort to streamline voter rolls, notably to remove people who had died or changed addresses, led to some people being unable to vote in the first round presidential election April 10. The state statistics agency reported that about 3,100 voters who were removed by error were restored to voting lists in time for the second round.

ARE THERE OTHER OPTIONS?

Mail-in voting was banned in 1975 amid fears of potential fraud.

People who can’t go to the polls for various reasons can authorize someone else to vote for them.

To do so, a voter must fill out a form ahead of time and bring it to a police station. Up to 7% of people voted by proxy in the last presidential election five years ago. French people living abroad vote in embassies or consulates.

Local authorities can organize vans or buses to pick up older people from nursing homes to bring them to voting stations, and prisons set up voting stations inside their facilities.

HOW ARE THE BALLOTS COUNTED?

Volunteers count the ballots one by one, by hand. Officials then use state-run software to register and report results.

But legally only the paper counts. If a result is challenged, the paper ballots are recounted manually.