This other answer is correct. I also immediately thought of the television series Babylon 5 (1993-1999).
But the question includes:
I need to find a film that I watched when I was a kid in 2000-2004 (don't remember the exact time). I remember the film about a person telling a story to his kids.
So someoneuseless remembers seeing a specific movie or a specific single episode where someone tells children the story of the the Human-Mimbari War. And I think that if they watched the television series they would have remembered the details much more clearly.
Thus it is my guess that they remember seeing either the first broadcast or a later one of the television movie Babylon 5: In the Beginning (January 4, 1998).
The synopsis in the Wikipedia article says:
...In 2278, Centauri Prime is in flames. A man surveys the destruction from a window of the Royal Palace. Two children, Luc and Lyssa, are later seen playing in the throne room and looking out the window. Their governess finds them and tells them that it is the Emperor's window and that only he can look out from it. The Emperor hears them and tells them to come in front of him. The Emperor is an aged Londo Mollari. Mollari allows Luc to be Emperor of the Centauri Republic for five minutes, during which time he may give any order he wishes. Luc asks for a story of great battles and heroes and villains. Lyssa wants to hear a true story. Mollari decides to give them both what they want and tell them the story of the Earth–Minbari War that took place 35 years prior while he was ambassador to Earth...
So the story teller is not telling it to his own children, although he might be acquainted with them if they are high ranking enough to be allowed to play in the imperial palace. By the way, the Centauri characters in this frame story are not human, they just happen by chance to look a lot of humans - though one episode of the series suggests that Centauri look a lot less human without their clothes.
And Mollari tells the kids the story of the Earth-Mimbari War which includes all the details which someoneuseless included in their question.
And thus it is my guess that someoneuseless remembers watching Babylon 5: In the Beginning.
And if they are interested in watching Babylon 5, one of the greatest science fiction shows of all time, maybe someone could point them to some discussion of the proper order to watch the various Babylon 5 episodes and TV movies.