I am not a lawyer; I am not your lawyer
In France, the Code de la Route (Article R413-15) outlaws the possession of devices that detect or disturb, or are intended to detect or disturb, the operation of devices or systems that record or regulate road traffic, or allow evasion of road traffic offenses.
This Article was last amended on 3 January 2012, and it is punishable by a fine of up to €1,500, confiscation of the device, and confiscation of the vehicle.
The law is not prescriptive about such devices, and this is likely intentionally so. This Article is technology-agnostic, and would apply to any device with such a purpose. You can therefore assume that all speed radar detectors are illegal.