Paris -- US President Barack Obama took time out from diplomacy Saturday, whipping the family off for a private tour of the famed Notre Dame cathedral, followed by dinner in a traditional century-old bistrot.

Just back from a D-Day commemoration on the site of the Allied landing, Obama and his family received a hero's welcome in Paris as crowds swarmed outside the city's Notre Dame cathedral and a restaurant in the shadow of the Eiffel Tower.

Thousands of cheering Parisians lined bridges over the River Seine as the motorcade swept from the cathedral to the restaurant, desperate for a glimpse of Obama, his wife Michelle, 10-year-old Malia and seven-year-old Sasha.

Sasha turns eight on Sunday, and early that day has another tourist stop on the calendar, a visit to the Pompidou Centre of modern art in Paris before it opens to visitors.

Saturday night, the US First Family chose a traditional French restaurant complete with red-chequered table-cloths and red-and-white awnings for a quiet dinner, but with only one of the girls.

Police blocked off the quiet narrow street and avenues nearby as the party drove up for a two-hour-and-some dinner at the old-style "La Fontaine de Mars", a moderately-priced establishment dating back to 1908 that prides itself on its "family atmosphere" and south-eastern French food.

A waiter told AFP "the atmosphere was very relaxed, there were five of them ... they said they had a wonderful meal and the president was extremely nice to the staff".

Obama chose roast lamb, while his wife, one of the girls and two guests -- "a US writer and a fifth person" -- went for beef fillets.

Earlier, applause and whistles erupted as Obama's 20-vehicle motorcade pulled in to the large square in front of Notre Dame cathedral, cleared of visitors and closed earlier than usual especially for the visit.

"It all went very well, it was a private visit by a family on holiday," said a spokesperson for the cathedral. "It was very agreeable."

With Paris abuzz, the presidential party spent more than an hour touring the 12th century cathedral, considered one of the finest examples of French gothic architecture.

The crowd, kept some 200 metres (yards) back behind barricades, erupted jubilantly when Obama daughters Malia and Sasha, on their first trip with dad since he became president, waved from a balcony high on the iconic building.

There was no disappointment from sightseers hoping to get inside the cathedral, simply excitement that an even bigger attraction was in town.

"It doesn't matter we'll come back tomorrow, we're so pleased to see Obama anyway," one of a group of Venezuelans said.

It was the Obama girls' second tourist treat in 24 hours after going up the Eiffel Tower on Friday with their mother for a birds-eye view of Paris, a visit that ended magically as the tower lit up the night sky with thousands of sparkling lights.

Security was tight at all stops, with sharpshooters in place at Notre Dame -- located on Ile de la Cite, an island in the heart of Paris on the River Seine -- and helicopters hovering overhead.

Obama, who is in France briefly for commemorations to mark the 65th anniversary of the Allied landing in Normandy, is due to fly home on Sunday, ahead of the family.

AFP/Expatica