Basel or Lille?

Neither city has a beach, but Basel has the better answer to a hot day: the Rhine float. You walk upstream with a swim bag and drift back past the old town on the current, from about June to early September. It is strong water for confident swimmers, not a sandy afternoon.

Lille's nearest swim is the North Sea at Malo-les-Bains, an hour away by train, where the water stays cool even in August and the wind is usually up. The Opal Coast dunes are for walking and sand yachting, so the coast is a bracing day out rather than time on the beach.

Lille has a cuisine of its own, while Basel largely borrows one. In the wood-panelled estaminets of Vieux-Lille you eat carbonnade cooked in beer, potjevleesch, waterzooi and Maroilles tart, mostly with Belgian and northern French ales. The Sunday market at Wazemmes adds a multi-ethnic side.

Basel cooks carefully, and its small top tier of fine dining is stronger than Lille's. Everyday menus, though, are Alsatian and Swiss-German, the local specialities come down to Läckerli and the Fasnacht flour soup, and ordinary meals feel pricey for what arrives. Locals often cross into Alsace or Baden to eat.

Both cities have a handsome old town and a major art museum, but Basel has many more great collections. The Kunstmuseum's Holbeins, the Fondation Beyeler in its Renzo Piano building, the Museum Tinguely and the Vitra campus over the border run from Old Masters to modern design. Around them stand the red sandstone Münster, the painted Rathaus and modern buildings by Herzog & de Meuron.

Lille's strength is concentrated in the Palais des Beaux-Arts, with its Flemish masters and relief maps, and in the Flemish baroque brick of Vieux-Lille and the Vieille Bourse. La Piscine in Roubaix is a memorable extra. Lille fills two or three days, and Basel needs three or four.

Lille goes out more. Its huge student population packs the cheap bars of Rue Masséna and Rue Solférino on Thursday nights. The cellar bars and beer cafés of Vieux-Lille suit a slower evening, and Belgium is close for later nights.

Evenings in Basel are quieter and more expensive: summer drinks on the steps of the Kleinbasel bank, bars around the Kaserne, and a few weekend clubs in old harbour buildings. Its trump card is Fasnacht in late winter, three days of drums, piccolos and lantern processions that start at four in the morning. It is worth timing a trip around.

Basel is far better placed for the outdoors. The Jura ridges begin at the city's edge, the Black Forest summits rise above 1,400m within an hour, and the Vosges lie to the west. All three have marked trails, and flat Rhine paths make for easy cycling into Germany and France.

Lille sits in flat, farmed Flanders, so time outdoors means the green loop of the Citadel park, canal towpaths and short walks on low hills such as Mont des Cats. The chalk cliffs of Cap Blanc-Nez and Cap Gris-Nez are the one dramatic landscape, and they take a long day.

Both are outstanding bases, and the difference lies in where they point. Lille is the base for cities. Brussels is about half an hour away, Ghent, Bruges and Antwerp follow close behind, and Paris, or even London for the determined, is in reach. Amiens cathedral, the squares of Arras and the First World War battlefields round out the list.

Basel offers more of a mix of towns and countryside. Colmar and the Alsace wine villages, Freiburg and the Black Forest, and Lucerne, Bern and Zurich are all about an hour away. The Roman ruins of Augusta Raurica are almost on the doorstep, and the Rhine Falls a little further.

Basel is the easier city for a family, above all because of the Zolli, one of Europe's best zoos and a short walk from the station. Children also get the Rhine ferries pulled across by the current, the toy museum and a free animal park in the Lange Erlen. Trams take prams easily, though the river is too strong for small children and the prices add up.

In Lille, the Citadel park makes a good morning, with its small zoo, playgrounds and flat paths for scooters, and the Forum des Sciences helps on a wet day. The cobbles of Vieux-Lille are hard going with a pushchair, though, and the bigger outings, a large Belgian zoo park and the Nausicaá aquarium at Boulogne, mean a day out of town.

Basel's green trams are the thing to envy. The network is dense, some lines carry on into Germany and France, and hotel guests ride free, so you rarely think about tickets. The four river ferries make crossing the Rhine part of the day, and the main station has direct trains across Switzerland and into both neighbouring countries.

Lille is just as easy on foot, with a flat, compact centre linking the Grand Place, Vieux-Lille and the Palais des Beaux-Arts. Lille Flandres and Lille Europe stand side by side near the old town, so setting off for the day is quick. Beyond the centre, though, there are only the two lines of the VAL, the world's first fully automated metro, and the tram to Roubaix and Tourcoing. They serve the metropolitan area but do not reach into the neighbouring country the way Basel's trams do.

Lille has more to offer a shopper. Chains line Rue Neuve, the Euralille mall stands by the stations, and the narrow streets of Vieux-Lille hold independent fashion, design shops and delicatessens. In early September the Braderie turns the whole city into a vast flea market.

Basel is tidier and smaller. Freie Strasse and Gerbergasse have watches, jewellery and chocolatiers, and there are a few design shops around Spalenberg and a pretty Christmas market by the Münster. Many locals do their high-street shopping in Germany.

Price is the widest gap between the two. Basel costs what Switzerland costs, from hotel rooms to museum tickets, and rooms become scarce during fairs such as Art Basel. Free trams for hotel guests and cheaper meals over the border only soften the bill.

Lille costs what any city in France does. Rooms are reasonable most of the year, estaminet meals and beer are fairly priced, the metro is inexpensive and the museums go easy on a budget. It is comfortable rather than cheap, but you feel the difference from Basel at every meal.

Basel has the stronger stage. Theater Basel puts on opera, ballet and drama known well beyond Switzerland for bold productions. The Stadtcasino, with its fine acoustics, is home to the Sinfonieorchester Basel and hosts the Kammerorchester Basel, and a long early-music tradition adds historical concerts. July and August are quiet.

Lille offers a dependable programme rather than a reason to travel: the Opéra on the Place du Théâtre, the Orchestre National de Lille and the Théâtre du Nord. It covers more ground in rock and pop, with touring acts at the Zénith and the Aéronef.

Basel is the calmer city and the better base for a spa day. The saline thermal baths at Rheinfelden are twenty minutes away, and the German spa towns of southern Baden are just over the border. Quiet Sundays and the riverbank suit an unhurried stay.

Lille offers hotel spas, tea rooms and café terraces, with the thermal baths of Saint-Amand-les-Eaux a short train ride away. Its pace is easygoing, but it is not a place that sends you home rested.