The beleaguered Louvre does not have a monopoly on bad news among France's museums if recent events are anything to go by.

It was third time lucky on Friday for the thieves who walked out of the Chatillonais Museum in the east of the country with a priceless gold torc.

Remarkably the thieves, who did not cover their faces, left with their loot via the main entrance in broad daylight. It was the second attempt raid in a week and the third in eight months at the same building.

The embarrassment, coming after last year's $102 million Louvre theft, is such that Culture Minister Catherine Pegard is bringing forward her presentation of a museum security plan, originally scheduled for the end of summer, to today.

Adding to the sense of crisis is the news that the reopening of Paris's Nissim de Camondo museum, which was due to happen this year, has been put back to 2030 after the cost of a $4.5 million restoration project ballooned to $26 million when serious problems were found in the building.

A pair of paintings sent to Poland from Ukraine for safekeeping after the Russian invasion are the subject of a legal argument over plans to prevent their return.

The works - Portrait of a Young Man by Alois Reyhan and Portrait of Roksolana by an unknown artist - are currently on show at the Museum of Central Pomerania in Slupsk on loan from Lviv Historical Museum.

They are part of the Lubomirski collection - built up over many years by an aristocratic family whose heirs are behind the legal action to prevent their return until their ownership is decided.

In a post on Facebook, the Ukrainian museum said it hoped "for an impartial and fair hearing of the case in accordance with the norms of international law, museum ethics, and current legislation" and it expected the pictures to be "safely returned to Ukraine".

The Frank Gehry-designed extension to the Philadelphia Museum of Art is on hold as it faces a multi-million-dollar deficit.

Its director Daniel Weiss said it was "not, at this time, appropriate" to consider the plan as the museum struggles with a deficit that could reach as high as $15.9 million in the next financial year.

That comes after two other years of deficits which Weiss told the Philadelphia Inquirer were "substantial, but solvable".

He said he hoped to balance the budget in three years and told the newspaper he expected yet-to-be-announced exhibitions to sell "large numbers" of tickets.

A Harley Weir image of singer Charli xcx is one of several works bought by the National Portrait Gallery in London using a $1.3 million donation from the Bukhman Foundation.

The picture was bought alongside a Barbara Walker self-portrait and Linder's Liverpool Sphinx photomontage.

It comes after work by Sonia Boyce and Hew Locke were bought with money from the foundation whose co-founder Anastasia Bukhman said it was "an honor" to support the gallery's purchases of contemporary work.

1 - Tickets have gone on sale already for this year's Frieze London and Frieze Masters. The art fairs, run by director Eva Langret, will be in their usual tents in the city's Regent's Park from October 14-18.

2 - The final decision on whether to grant protected status to a Keith Haring mural on the side of a house in Philadelphia has been put back to September. A decision was due last week but will now be considered by the city's Committee on Historic Designation meeting on September 16.

3 - Ralph Steadman is holding his first selling exhibition in 30 years at London's Tin Man Art gallery from October 2-11. It will include work from his collaboration with writer Hunter S Thompson.

4 - Matthew Barney has created a new work for the Aspen Art Museum AIR (Art in Residence) Festival which kicks off today. His large-scale sculpture, ZONE DEFENSE: Old Snowmass Parallax, is a permanent, site-specific take on a live performance piece he did last year.