Why did pope innocent III call for a crusade against heretics in France?

Pope Innocent III called for a crusade against heretics in France primarily to combat the Albigensian heresy, which threatened the unity and authority of the Catholic Church. The Albigensians, who held dualistic beliefs that contradicted orthodox Christianity, gained significant support in the region. By launching a crusade, Innocent aimed to restore religious purity, eliminate heretical teachings, and reinforce the power of the Church in France. This campaign, known as the Albigensian Crusade, also served to consolidate royal power and expand the influence of the Church in the region.