It is 100C
All Euro temp indicators are index marked at 20C intervals..

You may want to check the calibration/accuracy of both the sensor and the gauge.
Here is the sensor temp/ohms comparision chart for testing both.

60C-110 ohm
80C -67 "
100C - 38 "

I just keep a pre-measured 38 ohm resistor in my tool box and sustitude it at the sensor for gauge checking... that way, you do not have to wait for engine coolant to warm up..