Paying too much for rent? (Paris)

I am renting a 49m² one piece apartment in the 20éme in Paris. Although the monthly rent Protected content falls within the norm, my charges are Protected content per month (up from Protected content 2 years ago). I also get a bill each year for the difference of charges that my monthly payment doesn't cover. This year it's Protected content euros that I must pay. This seems excessive to me. Is this normal? What agency in Paris could I go to for answers?