Captured colors were almost uniformly kept by the victorious party as war booty although they could be occasionally compelled to return them after the conclusion of the conflict or even later depending on the circumstances. By the the late-19th century, however, the use of regimental colours on the battlefield were relatively rare leading to fewer opportunities to capture them and, as a result, the relative unimportance of their capture as priorities shifted to tactical victories with the dawn of mechanized warfare.

Les Invalides is one of the few museums to still maintain captured German colours from the First World War. The Kremlin Museum also probably has a substantial collection of Imperial German colours and certainly has a sizable collection of captured Third Reich paraphernalia.

You can see a brief display of captured German colours hanging in Les Invalides in 1914 here.

To give another, albeit historical, example: the "Garnisonskirche" (literally church of the garrison) in Potsdam, Germany is (in)famous for two things:

1.) Prussian kings were buried there, among them Frederick II. but against his will.

2.) "The day of Potsdam", a meeting of members of the newly formed German parliament, including Hitler, and president Hindenburg culminated in a ceremonial act in this church on March 21st 1933. The church was specifically chosen for propaganda purposes as Hitler wanted the day to symbolize the merger of old Prussian establishment with the Nazi movement, which isn't really surprising as many conservatives, especially aristocrats, didn't trust him.

The church was destroyed in WWII and since reunification there has been an endless debate about rebuilding it and one argument against it references what follows.

In this church the Prussian army displayed the colors and flags of their crushed enemies. According to German Wikipedia (and I hope nobody objects to the source in this instance) these were:

1.) 24 eagles and 2 colors from the Napoleonic Wars (this should directly answer your question)

2.) 1 color from the war against Denmark in 1848

3.) 25 colors from another war with Denmark in 1864

4.) 15 colors from the campaign against Austria in 1866

5.) 86 colors and eagles captured during the war against France in 1870/71

P.S.: Sorry for the long intro but I was born in Potsdam and couldn't resist.

There are many British churches and cathedrals associated with particular regiments, as well as regimental museums. In most of these captured enemy colours are currently displayed. In the Kremlin there are many colours displayed which were simply captured and seized when the regimental chapels were captured in 1945, and which were then sent to Moscow. For example, there are Bavarian Napoleonic colours in the Kremlin which were seized under such circumstances.