Cali Clarke

I did some digging and found a Ciro's in Paris in 1916 - it opened in 1912, 20 years after Ciro Capozzi opened the original Ciro's in Monte Carlo. Described in issue 157 of Tatler (8 May 1912) as having entrances on Rue Daunou/Rue de la Prix so it seems Harry worked at Ciro's Paris before he acquired the building. From The Sketch 1915 "Ciro's in Paris is beloved by the American colony"
Ciro's London opened in 1915, as a club to get around the 'cramping restrictions' on public restaurants.