Saudi princess robbed of luxury belongings in Paris heist
The 47-year-old princess, who had not set foot in the apartment since August, discovered on returning that bags, watches, jewellery and furs worth about $720,000 were missing.
The princess, whose name was not revealed, was hospitalised in a state of shock and has not yet spoken to police.
The thieves appear to have entered the apartment, situated near the swank Avenue George V in the heart of the French capital, without using force, the source close to the case said.
The bounty included around 30 Hermes bags worth between 10,000 and 30,000 euros each, a Cartier watch, jewellery and fur items.
Prosecutors have opened a formal investigation which will be handled by the Paris police's special anti-gang unit.
Le Parisien newspaper reported that an early suspect was a man who had been staying at the princess's apartment since August.
A spare set of keys to her home had gone missing, the paper added.