I will be there Sept.9th and am trying to figure out what to wear! I went to the website but it doesn't tell you much. Also how late do the trains run between Monaco and Cannes as we are staying in Cannes.
Coat and tie is required for the casino. See if the schedule shows up at Bahn.com.
The last train from Monaco to Cannes on September 9 leaves Monaco at 21:13 and arrives at Cannes at 22:19 (one hour six minutes). The fare is €9.40.
I just found this on Bahn and confirmed on SNCF, and I'm glad I looked, because I thought the trains ran later.
The ticket windows at Monaco station will be closed at that hour, and the ticket machines only take coins (no bills). So, be sure to buy a round trip ticket in Cannes before you go, or be sure you have coins to buy your ticket in Monaco.
You can get into the very front of the casino in regular rags during the day.
Also , make sure you DO NOT have a camera with you , you will not even be allowed in the door with one . I was there with my wife , so she held the camera while I took a glance just inside .
mjm,
As the others have mentioned, "correct attire" is required in the gaming areas of the Casino, which means jacket, tie and no sports shoes. THIS website provides some information. I didn't have the correct attire last time I was there so didn't bother going inside (I was also packing a large camera).