Paris

One quarter, and at least the fare is known before you start.

1. 1The taxi is a legally fixed flat fare rather than a meter: 56 euros to the Right Bank and 65 euros to the Left, valid in both directions. Traffic cannot change the price and there is nothing to negotiate.
2. 2If you take RER B instead, the ordinary 2.55 euro Metro-Train-RER ticket is not valid at the airport stations. The Paris Region to Airports ticket, 14 euros full price and 7 reduced, is the one that covers it.
3. 3Many restaurants close on Sunday and Monday and serving windows are shorter than elsewhere in Europe, so a six-hour window that lands between services buys you a brasserie or nothing.

Two quarters, ideally on the same bank.

1. 1The Marais and Canal Saint-Martin are one direction. Saint-Germain, the Latin Quarter and Montparnasse are the other, across the river.
2. 2A fixed-price lunch is often about half the evening price at the same restaurant, and weekday lunch usually works without booking where dinner wants roughly three days' notice.
3. 3Carry identification. You must be able to prove who you are on demand or within four hours at a police station, and covering your face in public is illegal with a fine of up to 150 euros, tourists included.

Both banks and Montmartre, which is about the most a day here holds.

1. 1The Marais, Canal Saint-Martin and Montmartre are the Right Bank day. Saint-Germain, the Latin Quarter and Montparnasse are the Left.
2. 2There is no dry season: about 634 mm a year spread evenly at 42 to 69 mm a month, so an umbrella earns its space in any month.
3. 3The FCDO records several cases of serious assault on RER line B, the line serving Charles de Gaulle, Orly and the Gare du Nord. Worth weighing against a fixed taxi fare late at night.