PARIS, Dec 13 (Reuters) - France will be hit by a sixth COVID-19 wave next month due to the emergence of the new, more contagious, Omicron variant of the disease while the country is still in the midst of the current, Delta-fuelled, fifth wave of the pandemic, according to a leading French hospital executive. "We haven"t said a word on the sixth wave, which is Omicron, which will come later, in January", Martin Hirsch, head of Paris"s AP-HP hospitals group, Europe"s largest hospital system, told RTL radio. British Prime Minister Boris Johnson warned on Sunday that the UK was facing a "tidal wave" of the Omicron variant of coronavirus and that two vaccine doses would not be enough to contain it. read more