'The roots, like those of the Mathusalem de Provence, extend 20 meters in diameter. Olive trees were probably introduced to France by the Phœnicians 3000 years ago, but this tree was more likely planted by the Romans in the year 400.'
I also took the following information from a website called Venerable Trees of the Earth.
'The tree was, in the 19th century, the property of the Vial brothers, called 'the dragons, the loggers, bonesetters and poachers.' They were determined to cut it down but Gabriel Hanotaux, the French politician and historian (1853 - 1944) intervened. He happened to be passing and was entranced by the beauty of the tree and bought it from the Vial brothers. It still belongs to his descendants but it is the municipality who care for it.' There is a street in the village called avenue Gabriel Hanotaux - seemingly, he invited Clémenceau, Poincaré and Briand to admire the beauty of this olive tree.
The hanging cage, by the way, contains a crèche - Roquebrune village is famous for its beautiful and varied cribs at Christmas.