A little oil painting that was saved from being auctioned for €1,500 in Spain earlier this year when experts believed it was the work of the Italian painter Michelangelo Merisi da Caravaggio has been awarded protected status as a cultural object.

The scourged Christ picture, which measures 111cm by 86cm, was taken off the market in April when it was discovered that it had been wrongly assigned to the circle of 17th-century Spanish artist José de Ribera.

Experts at Madrid’s Prado museum think there is “sufficient stylistic and documentary evidence” to imply it is an authentic Caravaggio, which may be valued as much as €50 million (£42 million).

The regional government of Madrid officially proclaimed the artwork a bien de interés cultural, or cultural property, on Wednesday, six months after Spain’s culture ministry slapped a precautionary export embargo on it.

It was regarded as “an example of the excellence and pictorial mastery of Italian naturalism,” which had a significant effect on the 17th-century Madrid school of painting.

The regional government said in a statement that “elements such as the psychological depictions of the characters, the realism of the faces, the luminous force that illuminates the body of Christ, the interplay of the three characters, and the communication it establishes with the viewer make this a work of great artistic interest.”

It said that the art needed to be protected regardless of who painted it, but that the evidence pointed to the Italian talent.

“The information that has surfaced in recent months, combined with expert studies, strengthens the theory that it is Caravaggio’s work,” according to the statement.

Because the painting is protected, its owners – the three children of Antonio Pérez de Castro, the founder of Madrid’s IADE design school, and the artist Mercedes Méndez Atard – must notify the authorities if they decide to sell it so that the regional government can decide whether or not to make an offer.

Thanks to at The Guardian whose reporting provided the original basis for this story.