A short trip to Paris, France.

Cologne Central Station
Book a room at the Hotel Eiffel Villa Garibaldi right near the Eiffel Tower.
Cross the river Seine, and walk up one of the Avenues toward the Arc de Triomphe.
Walk down the Champs-Elysées for some window shopping.
After crossing the Place de la Concorde, pass by the Louvre complex, and keep walking toward the Ile de la Cité to find the Notre Dame Cathedral.
If it’s not too late in the day, take the metro to Anvers. Walk up the Montmartre to Sacré-Cœur. On your way up, beware of the shameless pickpockets. Get back on the metro toward Invalides.
Check out Napoleon’s casket at the Hôtel des Invalides.
Get some delicious Korean Barbecue at Myung Ka on Boulevard Garibaldi. For dessert, pick up some treats at a nearby pastry shop.