Article R4451-15 of the French Labour Code
I.-The employer shall carry out measurements in the workplace when the results of the risk assessment show that exposure is likely to reach or exceed one of the following levels: 1° For the whole body: 1 millisievert per year; 2° For the crystalline lens: 15 millisieverts per year; 3° For the extremities and skin: 50 millisieverts per year; 4° For the radon activity concentration in the air for the occupational…