Beneath the glow of traditional chandeliers and modern spotlights, which illuminated its intricately carved stonework, the cathedral emerged reborn, its grandeur restored after more than five years of reconstruction.
For Catholics, it marks the revival of the city's spiritual heart, a place where faith has been nurtured for centuries. For the world, it signals the rebirth of one of global heritage's most famous landmarks.
The event was both solemn and historic. Archbishop Laurent Ulrich presided over the morning Mass, including the consecration of a new bronze altar.
The liturgy, attended by French President Emmanuel Macron, clergy, dignitaries, and guests totaling around 2,500 people, was closed to the general public. Nearly 170 bishops from France and around the world took part in the celebration, along with one priest from each of the parishes in the Paris diocese and one priest from each of the seven Eastern-rite Catholic churches, accompanied by worshippers from these communities.
Macron, in line with France's secular division of state and religion, did not take communion.
It is a milestone in Notre Dame's journey from ruin to resurrection - a process defined by extraordinary craftsmanship, nearly $1 billion in global donations and an unyielding determination to rebuild what seemed lost.
After the Mass, faithful attendees, priests, nuns, and other guests lingered in the cathedral, their awe evident. Many took pictures and selfies in front of the newly consecrated altar, the baptistery, and Notre Dame's vibrant rose windows, their joy mingling with reverence. Others knelt to pray at chapels dedicated to saints, savoring a spiritual intimacy many had not experienced since the fire.
"Being back here after all this time is overwhelming," said one attendee, who described the Mass as both a personal and collective occasion. Others praised the profound religious significance of Sunday's liturgy, which followed the official reopening ceremony on Saturday.
Some attendees had been invited by their diocese or religious organizations, while others woke before dawn for a chance to enter the cathedral.
Later on Sunday, an evening Mass will welcome members of the public who secured reservations last week. The Associated Press learned that tickets for this service were claimed within 25 minutes, underscoring Notre Dame's enduring ability to inspire devotion and curiosity.
What's more extraordinary is that this is taking place in a country with a strong emphasis on secularism and a low rate of church attendance.
The public watches on - from a distance
Public viewing areas along the Seine on Sunday morning drew hundreds of people who wished to witness the historic moment from afar, although their numbers were likely subdued by rainy and miserably cold weather conditions.
Retired engineer Claude Lancrenon, watching from a viewing area, expressed both awe and disappointment.
"There is so much security," he said, gesturing toward the barriers. "Yesterday, that seemed appropriate. But today, I had hoped it would be more open so we could approach the cathedral. I still hope we'll be able to get closer."
Tight security - akin to that of the Paris Olympic Games - reflected the importance of the occasion, ensuring the safety of dignitaries and the public alike as the cathedral re-entered its role as a global symbol of unity and resilience.
Nathalie Martino, a retired event organizer visiting Paris to see family, recalled the anguish of watching the cathedral burn.
"I cried so much that day," she said. "And now, here I am. I had to come. It was something I needed to do."
A sacred space reborn
Sunday's Masses follow Saturday evening's ceremonial reopening in which Ulrich symbolically reopened the cathedral's massive wooden doors by striking them three times with a crosier crafted from charred beams salvaged from the fire. As the doors swung open, choirs filled the cathedral with song and the cathedral's great organ - silent since the fire - resounded with majestic melodies.
Inside, the restoration reveals a cathedral transformed with now-gleaming limestone walls cleaned of centuries of grime. The restored stained-glass windows project dazzling patterns of color across the nave.
"No one alive has seen the cathedral like this," said the Rev. Olivier Ribadeau Dumas, Notre Dame's rector. "It is more than restored - it is reborn."
Sunday morning's liturgy consecrated the new altar, a pivotal moment in Notre Dame's return to full liturgical life.
The altar houses relics of five saints tied to Paris, including St. Catherine Labouré and St. Charles de Foucauld, continuing a centuries-old tradition of embedding sacred artifacts at the heart of worship spaces. The consecration, involving holy water, chrism oil, incense and prayer, transforms the altar into a sacred centerpiece of the cathedral.
A moment of unity
The reopening of Notre Dame is more than a religious milestone, it is a moment of cultural and national unity. Macron, who vowed to restore the cathedral within five years after the fire, attended Saturday's ceremonies and called the project "a jolt of hope" for France, a nation often divided by political crises.
The Sunday Masses underscore Notre Dame's dual role as a place of worship and a symbol of communal resilience. They also ensure that members of the broader Catholic community can partake in the cathedral's spiritual revival.
"This was not just about restoring a building. It was about restoring the heart of the nation," Dumas said.
Challenges overcome
The path to restoration has been fraught with challenges. Lead contamination forced work to pause, and the COVID-19 pandemic added delays. Yet the project, overseen by architect Philippe Villeneuve, has been hailed as a triumph of human ingenuity and collective resolve. Cutting-edge fire prevention systems, including thermal cameras and a misting system, have been installed to safeguard the cathedral's future.
Villeneuve described the effort as "restoring not just a building but the soul of a nation," emphasizing the personal and national significance of the work.
A sacred future and an 'octave'
With its spire once again piercing the Parisian sky, Notre Dame is poised to reclaim its role as a global beacon of faith and art. The cathedral, which previously welcomed 12 million annual visitors, is expected to draw 15 million in its new chapter.
This monumental revival is not confined to a single day. Ulrich has announced an "octave" of celebrations - eight days of special religious services, each with its own theme, running through Dec. 15. These daily liturgies, open to diverse groups from local parishioners to international pilgrims, emphasize Notre Dame's role as a unifying spiritual hub.
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Yesica Brumec, John Leicester and Bela Szandelszky in Paris contributed.
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Associated Press religion coverage receives support through The AP's collaboration with The Conversation US, with funding from Lilly Endowment Inc. The AP is solely responsible for this content.