Syrian President Bashar al-Assad's uncle, suspected of using ill-gotten gains to build a property empire in France, has been charged with corruption, French officials say.

Rifaat al-Assad, 78, who commanded Syria's internal security forces in the 1970s and early 1980s, was charged on June 9 with receiving embezzled funds and tax fraud, a spokesman for the financial prosecutor's office said on Tuesday.

A French judge ordered Rifaat al-Assad be prohibited from leaving France, with an exception for receiving medical care in the UK, according to one of the two non-governmental organisations, Sherpa, which filed complaints in 2013 and 2014 that led to the investigation.

Sherpa claims Rifaat's fortune was stolen during his time at the heart of the Syrian regime.

In the probe, headed by Renaud van Ruymbeke, investigators estimated that Rifaat and his family amassed about $100m worth of property in France, mainly through companies registered in Luxembourg, between 1984 and 1988.

The Assad family claims the fortune was the result of gifts from wealthy Saudi supporters, including former King Abdullah, with whom he shared a love of horse-racing.

Van Ruymbeke has said that Rifaat has provided proof only of a $10m gift from Abdullah in 1984, the source told AFP.

'Exile with nothing'

The properties include a chateau and stud farm north of Paris, two mansions, two apartment blocks and a plot of land in the French capital, as well as offices in southern Lyon.

Rifaat, who has four wives, told investigators that he "had nothing" when he left Syria, having always given his wages away to the poor, according to a source close to the investigation.

He was forced into exile in 1984 for trying to overthrow his older brother, the late Syrian President Hafez al-Assad.

Then French President Francois Mitterrand invited Rifaat to France, awarding him the Legion d'Honneur two years later.

Syrian Foreign Minister Abdel Halim Khaddam, who also lives in France, told investigators that Hafez al-Assad gave his brother about $300m in 1984 to get rid of him.

Of that, $100m was in the form of a loan from the Libyan government, a source close to the investigation told AFP.

Rifaat is notorious for his role in putting down an uprising by the Muslim Brotherhood in the Syrian city of Hama in 1982. At least 10,000 people were killed.

Source: Agencies