that is a very interesting jeton!!
It was used in the 50s till early 60s. It is a pretty rare jeton.
I still need that one for my collection. (And I have a big Monaco collection )
Your jeton also looks like an error jeton. Normally the serial number is directly under the word "Monaco".
And the "normal" jetons do not have any printing outside the center. Please see my 100 jeton from that issue.
Hope that helps a bit.

BTW, please contact me if you would like to sell the jeton

Regards,
Björn Zabel
www.casino-chips.de
R-5585