Strasbourg is a great walking city, with many pedestrian zones. The reddish Gothic Notre-Dame Cathedral stands out, as do cathedrals in so many French cities and villages. The astronomical clock inside is intriguing. Around the cathedral are half-timbered buildings, and myriad restaurants.
The sizeable square is a favourite place for street performers of all sorts, and some mimes are likely, in true French fashion.
A little further afield is the Orangerie, a pleasant park with lovely flowers and a small zoo. If you have never seen a stork, here is your chance, as there are several (not only here, but elsewhere in Alsace too).
Strasbourg is an important city as it is home to the European Parliament. Tours are possible.
But back to the city center and one of the nicest areas of Strasbourg, the area known as La Petite France. Situated near canals, locks and the River Ill, this area is full of fascinating architecture, narrow streets, and restaurants and homes, lovingly decorated with flowers,and overlooking the water. 14th-century towers further add to the history. A canal cruise makes for a pleasant and relaxing ride, with a different perspective of La Petite France and other parts of Strasbourg.
If you want to go further, the Rhine River is the border between France and Germany. It is a major waterway for both the workaday world and cruises. Regardless of your choices, put on some good walking shoes and enjoy the city on foot!