The Italian War of 1494-1498 began when the king of France at the time, Charles VIII, had tried to make good of a remote claim that the Italian state of Naples was rightly his. At the time Naples was in control of the Spanish, and it had been under the control of the Spanish since the 1440s.
Charles conquered Naples in 1494 pretty easily, so he continued on to try to conquer Milan, he probably felt pretty invincible at that point. But he was betrayed, and eventually was forced out of Naples by the League of Venice which consisted of other Italian States. His forces began to die out from disease. He himself died in 1498 from an incident that consisted of him hitting his head on a door frame. This in turn was the end of the war.
In short, the Italian war of 1494-1498 did not amount to anything for the French, and actually was a complete loss. This is one of the many examples of how something looks like it is going incredibly well, but ends up being a complete failure.