2. King Carl XVI Gustav of Sweden
The Swedish king, 64, had visited nightclubs and had an extramarital affair during the Nineties, a biography by three journalists Thomas Sjoeberg, Deanne Rauscher and Tove Meyer revealed.
In 2010, the king had to issue an appeal to journalists to leave him in peace, while admitting that the events took place "far back in time".
3. Prince Harry of Britain
Prince Harry was videotaped nude while playing strip pool in Las Vegas in August, 2012.
These pics were flashed in a French magazine, and the British media, normally conscious about not offending the monarchy, put up a defence for its prince.
Prince Harry was also involved in trouble for excessive drinking, smoking marijuana, cheating in exams and wearing a Nazi uniform to a costume party. The palace maintained a studious silence.
4. Prince Albert II of Monaco
The Prince of Monaco publicly confessed in 2005 that he had an illegitimate son with a former flight attendant from Togo, and fathered a daughter out of wedlock in 1992.
A long-time bachelor, Prince Albert II had a strong of illicit affairs, culminating in his wedding to Princess Charlene in July 2011.