How was Christmas introduced to France by the Romans in the 12th century?

I don't understand how this date could be acurate. 300 to 500 AD Romans became Chrstian. By 1200 AD Gothic cathedrals were everywere in France, England, Germany and prety much everywere. The exact day of the Christ child's birth has never been pinpointed. Traditions say that it has been celebrated since the year 98 AD. In 137 AD the Bishop of Rome ordered the birthday of the Christ Child celebrated as a solemn feast. In 350 AD another Bishop of Rome, Julius I, choose December 25th as the observance of Christmas.

In the late 300's, Christianity became the official religion of the Roman Empire. By 1100, Christmas had become the most important religious festival in Europe, and Saint Nicholas was a symbol of gift giving in many European countries. During the 1400's and 1500's, many artists painted scenes of the Nativity, the birth of Jesus.

The Roman's celebrated their god Saturn. Their festival was called Saturnalia which began the middle of December and ended January 1st. With cries of "Jo Saturnalia!" the celebration would include masquerades in the streets, big festive meals, visiting friends, and the exchange of good-luck gifts called Strenae (lucky fruits).

The Romans decked their halls with garlands of laurel and green trees lit with candles. Again the masters and slaves would exchange places.

"Jo Saturnalia!" was a fun and festive time for the Romans, but the Christians though it an abomination to honor the pagan god. The early Christians wanted to keep the birthday of their Christ child a solemn and religious holiday, not one of cheer and merriment as was the pagan Saturnalia.

But as Christianity spread they were alarmed by the continuing celebration of pagan customs and Saturnalia among their converts. At first the Church forbid this kind of celebration. But it was to no avail. Eventually it was decided that the celebration would be tamed and made into a celebration fit for the Christian Son of God.

Some legends claim that the Christian "Christmas" celebration was invented to compete against the pagan celebrations of December. The 25th was not only sacred to the Romans but also the Persians whose religion Mithraism was one of Christianity's main rivals at that time. The Church eventually was successful in taking the merriment, lights, and gifts from the Saturanilia festival and bringing them to the celebration of Christmas

France was not under the influence of Rome in the 12th century. The western Empire had ended 7 centuries earlier. Your question is therefore meaningless.

"French Christmas customs

"In 1100, Godefroy de Bouillon’s successor, his brother Baudouin, was crowned in the basilica of Saint Mary of Bethlehem. Later, King Jean-le-Bon founded the Order of the Star in honour of the manger; it remained in existence until 1352. In 1389, French crowds shouted Noël! Noël! in welcoming Queen Isabeau of Bavaria to the capital.

Thus Christmas gradually became both a religious and secular celebration which, in fact, until the end of the Middle Ages, was confused with the celebration of the New Year."