Renault Megane 1.6e Sport temp readings

Hi,

I have had ever since i bought the car 4 years ago, low temp engine temp readings on the dash way below normal operating temp....needle on or around second mark on display. I have changed thermostat and temp sensor to no avail....also when i am in stationery traffic the car will get hot very quickly (then fan kicks in)......just seems odd the car runs with such low temp readings any ideas? Thanks