Place aux Herbes is the loveliest small square in old Nîmes — a triangular plaza in front of the cathedral, ringed by old town houses, cafés, and a small market on Saturday mornings. The trees provide shade in summer; the cafés put their tables out year-round.
It's one of those spots where it makes sense to sit and watch rather than walk. Combine with a visit to the cathedral and the Museum of Old Nîmes, which adjoins the square.