It was actually more of Dwight D Eisenhower's decision. His primary objective was to reach Berlin before the Red Army did. The Allies wanted to secure Berlin, end the war in Europe. And this would enable US to concentrate on the Pacific front, where it was locked in an intense conflict with Japan.
One more factor, was that Hitler had ordered the destruction of Paris, should it fall into Allied hands. Eisenhower did not want Paris to suffer the fate of Warsaw, that was burnt down to the last brick. With Paris having an emotional connect as the cultural center of the Western world, Eisenhower, did not want to risk a complete destruction.
Eisenhower also wanted to avoid another Stalingrad/Leningrad like situation, that would have meant committing a whole lot of resources and men for the retaking of Paris. It was estimated that around 4000 tons of food per day, as well as significant amount of money on rebuilding, manpower would be needed the moment Paris was liberated. Already pressing towards Germany, that would have meant diverting much needed resources for the city.