Russia said Thursday that a sprawling collection of artworks by the likes of Van Gogh, Cezanne, Matisse and Monet -- the so-called Morozov Collection -- has been safely returned after the show proved a runaway success in Paris.

Nevertheless, the French government said that two key paintings had been held back due to Western sanctions against Russia over its military operation in Ukraine.

The Morozov Collection drew a near record-breaking 1.25 million visitors to the swish Louis Vuitton Foundation in the Bois de Boulogne between September 22 and April 3.

In fact, the show proved such a success that it was extended from its initial end-date of February 22, two days before Russia sent in troops to its pro-Western neighbour.

"The Morozov Collection has returned to Russia. At the moment, the exhibits have already been delivered to state museums," Culture Minister Olga Lyubimova said on messaging app Telegram.

It took nearly 20 days to secure the return of the artworks, Lyubimova said, praising a "great team effort", and the entire collection would now go on show this summer at Moscow's Pushkin Museum.

The collection, built up by brothers Mikhail and Ivan Morozov during the late 19th and early 20th century, had never before been seen as a whole outside Russia.

In April, the French culture ministry said that two pictures were to remain in France -- a self-portrait by Russian artist Pyotr Konchalovsky owned by sanctioned Russian oligarch Petr Aven; and a work by Russian painter Valentin Serov, which belongs to the Fine Arts museum in the Ukrainian city of Dnipro.

The Ukrainian authorities had asked for the latter painting to remain in France until the situation improves.

After Russian President Vladimir Putin sent troops to Ukraine on February 24, the EU adopted a series of sanctions including those prohibiting the sale, supply, transfer or export of luxury goods -- including works of art -- to Russia.