Some of the earliest manuscripts with polyphony are organum from 10th century French cities like Chartres and Tours. A group of musicians from the Abbey of St. Martial in Limoges are especially important, as are the 12th century Parisian composers from whence came the earliest motets. Secular music in medieval France was dominated by troubadours, jongleurs and trouveres, who were poets and musicians known for creating forms like the ballade (forme fixe) and lai. The most famous was Adam de la Halle.
The Notre Dame school was a style of polyphonic organum that flourished at Paris' Notre Dame Cathedral between about 1170 to 1250. The only composers whose names have survived to the present are Léonin and Pérotin. These two are believed to have written the Magnus Liber, a comprehensive book of organum.
The motet evolved from the Notre Dame school when upper-register voices were added to discant sections, usually strophic interludes, in a longer sequence of organum. Usually the discant representing a strophic sequence in Latin which was sung as a descant over a cantus firmus, which typically was a Gregorian chant fragment with different words from the descant. The motet took a definite rhythm from the words of the verse, and as such appeared as a brief rhythmic interlude in the middle of the longer, more chantlike organum.
In the 12th century, traveling noblemen and musicians called troubadours began traveling southern France. Inspired by the Code of Chivalry, troubadours composed and performed vernacular songs (in contrast to the older tradition, dating back to the 10th century, of goliards. Provence was the region with the most troubadours, but the practice soon spread north and aristocrats like Adam de la Halle became the first trouvères. Contemporaneous with the troubadours was the rise of the trouvères, another itinerant class of musicians, who used the langue d'oil, while the troubadours used langue d'oc. This period ended abruptly with the Albigensian Crusade, which decimated southern France.