ROME, July 20, 2008 (AFP) - Italian police said Sunday they have arrested a French tourist found beating his four-year-old daughter into a coma in the centre of Rome.

A spokesman said the man, in his late 30s, 'was violently banging his daughter's head against the marble base' of the Vittoriano monument in Piazza Venezia when officers arrived late on Saturday evening.

The girl is in a critical condition following an operation for serious head injuries, with the mother -- on holiday in Turkey and unaware they had left Paris -- taking the first flight to Rome.

Passers-by had attempted to restrain the tourist before calling the police.

The man was found banging his own head against the monument when they arrived. Officers said medication was also found, with his wife indicating he had previously been hospitalised due to psychiatric problems.