score:2
I would like to share my experience while visiting Monaco during F1. I was there on the 25th of May (Thursday) on first half of the day (practice session - track closed) and on the 26th (Friday) during second half of day (track opened to public). The schedule during these days can be found here https://www.monaco-grand-prix.com/en/programme-2542-f1-monaco-451.html
Monte Carlo casino was closed during F1 practice and, in fact, any other time when track was used and would be reopened around 19:00. This included whole area around the casino. Only Café de Paris was accessible. Additionally it was not possible to get a nice view of the Monte Carlo on Thursday. It is, however, when track is opened to the public.
Tourist places were open on Friday, however, for example, Prince's Palace of Monaco could be visited only until 15:00 (usually at least 18:00) and it was closed on Saturday and Sunday.
In general I would advise any visitor willing to explore Monaco during F1 to contact their tourist info center before.
Upvote:5
From the Monte Carlo casino website, there is no mention about being closed during F1 weekend: it is opened everyday from 2PM. So it must be opened.
I hope you already have your hotel and don't want to use your car as the circuit is really in the main streets:
But you will probably be able to walk around the city if your are 1 block away from the track.
In addition, as @AndyT commented:
They also open all the roads up every evening, after whatever practice/qualifying/race sessions have finished. (Source: my brother-in-law who went to the Monaco GP a couple of years ago.)