Paris or Istanbul?

Neither city is a beach destination, but Istanbul at least has the sea close by. The sandy Black Sea beaches at Kilyos and Sile are about an hour away and warm enough in high summer, though the currents mean you should swim only where lifeguards are on duty. The pebbly coves on the Princes' Islands make a good half day.

Paris has only the summer sand laid out along the riverbanks, swimming spots on the Bassin de la Villette and in the Seine, and some handsome public pools. Its nearest real coast is Normandy, two hours away by train, where the Channel stays cool.

Istanbul brings the cooking of every Turkish region into one city. You get trays of the day's stews in a lokanta at lunch, fish sandwiches by the Galata Bridge, long evenings of meze and rakı in the meyhanes of Beyoglu and Kumkapi, and Kadikoy's market streets for grazing. For Turkish food it is hard to beat, but there is far less choice beyond it.

Paris goes further, because eating well is part of ordinary life there. Every neighbourhood has its boulangerie and cheese shop, and there are markets such as Aligre, zinc-counter bistros, small inventive neo-bistros in the east of the city and haute cuisine at the top. Its immigrant kitchens widen the choice again, from couscous in Belleville to pho in the 13th.

These are two of the world's great sightseeing cities, and Paris pulls ahead on museums alone. The Louvre, the Orsay, the Orangerie, the Pompidou and the Cluny sit alongside the Gothic Sainte-Chapelle and Notre-Dame, all set in the matching stone streets of Haussmann's centre. Art lovers will find nothing in Istanbul to match it.

Istanbul's riches are of another kind: Byzantine and Ottoman monuments such as Hagia Sophia, Topkapi, the Süleymaniye and the Chora mosaics. They cluster on the historic peninsula and continue along the Bosphorus. Here the draw is architecture and empire more than galleries.

Both cities stay up late, and the difference is one of style. A Paris night starts on a terrace or in a wine bar and spreads across the east, through Oberkampf, the Canal Saint-Martin and Belleville. When the bars close around 2am the clubs take over with house and techno, though doors can be selective.

Istanbul packs its nightlife into a few districts: Beyoglu's rooftop bars and meyhanes that end in singing, the younger bar streets of Kadikoy and Moda, and summer clubs on the Bosphorus shore. Beyond those areas the city goes quiet, and the heavy tax on alcohol makes drinks expensive.

Neither city has wild country nearby, so the outdoors means water and parks in Istanbul and woods and gardens in Paris. In Istanbul you can walk along the wooded Bosphorus or cross it by ferry, see the April tulips in Emirgan, walk the trails of Belgrad Forest and cycle on the car-free Princes' Islands.

Paris is flatter and more formal, with the Luxembourg, the Buttes-Chaumont, the large woods of Boulogne and Vincennes and easy rides by bike-share along the canals. Its advantage is Fontainebleau, forty minutes away by train, whose sandstone boulders draw climbers. Getting out of Istanbul takes far longer.

Paris is far ahead here. Versailles, Fontainebleau and Chantilly are each less than an hour away, and Chartres and Giverny are easy trips. Fast trains reach Reims, Rouen and Tours, the gateway to the Loire, in about an hour or so, which is enough to fill a second week.

Istanbul's best outings are by water: the Princes' Islands, or a cruise up the Bosphorus to Anadolu Kavagi. Bursa makes a fine town day, but Edirne and Iznik are long days, and Gallipoli and Troy need a night away.

Paris is easier with children, mainly because there is so much for them to do. Disneyland and Parc Astérix are close by, and in the city there are the Cité des Sciences, the natural history galleries at the Jardin des Plantes and the toy boats in the Luxembourg. Metro stairs and small hotel rooms are the main trials.

Istanbul's warmth towards children is its great strength, and the ferries and the Rahmi M. Koç Museum go down well. But steep cobbled hills, crowds at the sights and long transfers wear out young children, and pushchairs struggle even more than in Paris.

Paris is the simpler city to get around. Its centre is compact enough to walk from the Marais to Saint-Germain, there is usually a metro station a few minutes away, and the RER runs out to Versailles and the airports. The downsides are stairs and confusing changes between lines.

In Istanbul one card covers the tram, metro, Marmaray and ferries, and the ferries are a pleasure in themselves. Distances are much greater, though. The hills are steep, the T1 tram is packed where it passes the main sights, and road traffic is slow.

Istanbul shops the old way. The covered streets and hans of the Grand Bazaar are full of carpets, kilims, leather, lamps and ceramics, and the Spice Bazaar by the Golden Horn sells spices, dried fruit and Turkish delight. The streets between the two are still grouped by trade, and haggling is expected. Nisantasi has the designer labels and Cukurcuma the antique shops, but crafts are the real reason to shop here.

For anyone who travels to shop, Paris is in another league. Luxury fashion was born there, and the great houses still keep their flagships on Avenue Montaigne, while Galeries Lafayette and Le Bon Marché are worth a visit for their buildings alone. The Marais adds independent designers and vintage, the nineteenth-century covered passages hide old specialist dealers, and the Saint-Ouen flea market is a vast maze of antiques.

Istanbul is much easier on the wallet. Transport and ferries cost very little, tea, simit and lokanta lunches are cheap, and staying in Kadikoy makes money go further. What pushes costs up are hotels in Sultanahmet, the entry fees foreign visitors pay at the main monuments and the heavily taxed alcohol.

Paris is expensive almost everywhere, with small, costly hotel rooms, terrace meals that add up and full admission at the museums. Bakeries, markets, set lunches and the free collections of the city's own museums help, but they soften the bill rather than change it.

Paris offers far more for an evening out. It has two opera houses, the Palais Garnier and the Bastille, plus the Philharmonie, concerts in the Sainte-Chapelle, jazz cellars and cabaret in Pigalle. Its theatre is mostly in French.

Istanbul's formal stage centres on the Ataturk Cultural Centre and on summer festivals held in historic courtyards. Its more memorable side is traditional: a Sema ceremony in a dervish lodge, or fasil musicians playing between the tables of a meyhane.

This is one of Istanbul's clearest advantages. Sinan's sixteenth-century hammams, such as the Cemberlitas, Haseki Hürrem and Kilic Ali Pasa, are still working. You lie on heated marble under domes pierced with star-shaped skylights while an attendant scrubs you. A slow ferry or a tea in Kandilli adds the calm the city otherwise lacks.

The Paris hammam tradition came with its North African communities, and the steam rooms and mint tea of the Grande Mosquée are pleasant but modest. Beyond that, rest in Paris means a hotel spa, a chair in the park or an evening walk by the Seine.