This is the unlikely venue for the second outing for Leonardo da Vinci’s “Earlier Mona Lisa”, an exhibition showcasing a portrait also called the “Isleworth Mona Lisa” and designed to “prove” that Leonardo really painted it. It was first shown in Singapore last year.

The multimedia presentation, held in a low-ceilinged former hotel, features just one painting — the “Mona Lisa” — which its owners maintain was painted by Leonardo 10 years before the Louvre version. Leading up to it are interactive computer displays and posters all designed to hammer home its authenticity, including the statement: “Twenty-eight out of 29 experts believe this is either possibly or certainly a painting created by da Vinci.”

Others beg to differ, among them the renowned Leonardo scholar Martin Kemp. “Everything points to the Isleworth painting being a copy,” he has written. “There are families of copies of the Mona Lisa. This family … is not the best.”

The inauguration of the Shanghai exhibition was accompanied by a great deal of hoop-la. The portrait arrived last month “under maximum security protection” in a 500kg, bulletproof case, say the promoters. A Chinese TV star and former Miss Asia, Kristy Yang, was shipped in to say how much she liked the work, which was presented to the media at a “select invitation-only ‘Box Opening Ceremony’”.

New evidence, say the organisers, confirmed that the work is “without a shadow of doubt” by Leonardo himself and so makes a “groundbreaking change to global Art History”.

So what is it doing in a shopping district in Shanghai?