That's the serial number (for security purposes).

Jim exhibited a jeton that did not follow the graphics you described as being "STE..." which could be code: Day's 9a if it's 32mm -- and Jim's example; code: Day's 9a, has graphics other than you stated in your subject line as being "ste... (actually "STE...")" and a different size, being approx. 38mm.

I do not know is there is a "ste..." or "STE..." in what may have been yellow.

At this point could you please give us the size of the "200" jeton (chip) you seek info on? Otherwise, if your example is Day's 9a, w/o any revaluation stamp; which was done on either the two "00" by stamping a bar over them or a comma between the "2" and first "0" of the "00" to conform with the French Monetary Reform Act when in the early-60s when every 100-French francs became one "NF" (New franc).

I'd say the value of the example you describe is approx. $10-$20 since they are quite common and ould be known in a few colors... unless you have a previusly unknown color/size.

In any event, the suggestion given that you come here seeking information was excellent advice....