It's not about scams, it's about commercial telemarketing calls.
Scams have been heavily hit in January when the French regulator mandated the telcos to implement a complete block of spoofed phone numbers (it's not an actual hard block, but unauthenticated calls will be market as "private number" which are ignored by most people already).
There will always be scammers who register an actual phone number to run their scams, but this rule will at least stop the constant phone harassment that made everyone unplug their landline phone.
Scams have been heavily hit in January when the French regulator mandated the telcos to implement a complete block of spoofed phone numbers (it's not an actual hard block, but unauthenticated calls will be market as "private number" which are ignored by most people already).
There will always be scammers who register an actual phone number to run their scams, but this rule will at least stop the constant phone harassment that made everyone unplug their landline phone.