I weigh 95kg &172cm. I train 5 days per week& lift weights but my muscles mass is over weight & I easily gain muscles as well as gaining fats. Should I decrease the weights &increase repetitions to decrease my fat mass or what is the best approach?

Eat fewer calories. There is no healthy way to lose weight quickly. Extremely low calorie diets don't work, because such diets cannot be continued for long, and the dieters gain their weight right back. A person needing to lose "fat mass" should be evaluated by her doctor to be sure there are not medical conditions related to that. Then then math always works: fewer calories IN equals LESS fat stored in the body.