Between Monaco and the Menton, very close to the Italian border, lies Roquebrune-Cap-Martin
As with some of the other peninsulas (Caps) on the Riviera, you can walk around the entire perimeter, enjoying beautiful views over the Mediterranean, and, in this case, on the city of Monaco.
The most recent time I did this walk was in late April; weather was a bit blustery, not too hot, so perfect weather for a relatively easy walk.
This walk takes about an hour, although you can go as slow as you like, soaking up the views, enjoying the panoramas as you go along.
On the western side you have splendid views of Monaco, on the easter side you'll be able to see the city of Menton.
You can start the walk on either side; I parked on the eastern side, see the precise location indicated on the map below.