For getting around Paris you have a lot of options - an efficient metro, the fantastic Velib' bike rentals - but taxis are a basic necessity for any business traveller. But taxis are far less plentiful than in London or New York, and it can be a hassle to find them late at night or outside the city centre. Save yourself the hassle and hire one by phone. The best number to use is G7's English-language service; it's much easier than using the French one!
G7 taxis in English, 01 41 27 66 99http://www.taxisg7.fr/