There were lots of Turf Club in several european countries (including Portugal), that were clubs borned in the end of 19 century,that agregate people who like horse activities, like horse racings,that were organized by the clubs, etc. These clubs also runned like the english club ( for men and with gambling rooms to the their restricted menbers).
I THINK this plaque must be from France- the value is 500 F ( franc français- french franc)