Le Jardin des Deux Rives is located in both France and Germany, with the River Rhine separating the two countries and dividing the park into two parts. The French side is situated in the city of Strasbourg, where the German side belongs to town of Kehl.
The park was inaugurated in 2004 as a symbol of friendship between France and Germany. In fact, during the NATO summit held in both Strasbourg and Kehl in 2009, the countries' leaders, Angela Merkel and Nicolas Sarkozy, met in the middle of the bridge that straddles the river and connects the two sides of the park.
There are two huge green spaces on each bank of the Rhine, where you can go for walks, have picnics, play games, and ride your bike, amongst other things.
In addition to this, there is a huge bridge that straddles the Rhine, and if you stand right in the middle of it, you will be in France and Germany at the same time! Besides, I entirely recommend the views from the Passerelle des Deux Rives anyway. This bridge is a work of modern art and you can cross it both on foot, by bike or even in a wheelchair, with some breathtaking views. The architect that was tasked with the construction of this bridge was the Parisian, Marc Mimram.
When I went, there was an area that depicted the flag of the European Union, with blue flowers for the background and yellow ones for the stars.
Every summer, an outdoor concert organised by the Orchestre Philarmonique de Strasbourg [the Strasbourg Philharmonic Orchestra, in English] in this park and is called "La Symphonie des Deux Rives".
I recommend travelling there by bike because the area itself is quite substantial and will take a significant amount of time to make your way around it. If you don't have a bike, however, you can also get there by bus or by car. The bus routes that will take you there from Strasbourg city centre are lines 2 and 21. You can catch the number 2 at the Observatoire in the direction of the Passerelle des Deux Rives, alighting at "Jardin des Deux Rives". Whereas, you can catch the 21 at Jean Jaurès towards Kehl Stadthalle, again alighting at "Jardin des Deux Rives".