It's the short phone number to dial to get access to the portal where you enter the name of the service you want. There were different ones with different prici

It's the short phone number to dial to get access to the portal where you enter the name of the service you want. There were different ones with different pricing. 3614 was cheaper (no revenue for the service I think), 3615 was regular and 3617 was expensive (you could buy stuff, like games by staying online). While most services were accessible through this portal (operated by the French telco), you could also dial a "regular number" to access some services à la BBS.