Normally, À means “in” when asked after the birth date, i.e. the location where you were born.

The third field (commune) is an administrative division in France, but it might not have a strict equivalent in other countries. That’s a town/municipality and what is stated as place of birth in many documents.

If you want to provide different information in these last fields, you might give your hour/minute of birth in the à one, because à can also introduce that information (that is never asked for by universities though…)