The document, which once belonged to the cathedral of Puy-en-Velay in the Auvergne region, was acquired by an anonymous buyer after a heated bidding war, said Michaela Strebl of the Dorotheum auction house.
Starting at €50,000, offers for the book - a complex liturgical mix of texts and music - quickly rose, thanks to "huge interest from international buyers", she said.
"The manuscript has sensational value because it is in exceptional condition for a document that has never been restored," Strebl added.
Written around the mid-11th century, just before the First Crusade, most of the 276 pages are intact and embellished throughout with illuminated initials.
It is the oldest known manuscript to originate from the French diocese, an important cultural centre in the Auvergne region and beyond, as one of the starting points of the Santiago de Compostela pilgrimage.
Recognising the book's scientific and historical significance, the department of Haute-Loire, where Puy-en-Velay is located, launched a campaign to raise funds for the auction, but in the end fell short of the winning bid.
"We are of course very disappointed," the director of Haute-Loire's archives, Martin de Framond, told AFP.