Well, after we invaded, we discovered all that evidence about French arms sales (in violation of the embargo) and the kickbacks Saddam made, in the oil for food scandal. Also, Chirac might have been concerned about more evidence coming out on how Saddam financed Chirac's party (the Rally for the Republic) when it was getting started. Also, it came out how the French oil company Total induced Saddam to slaughter the marshland Shiites and dry up their land, in order to make things safe for oil exploitation. There are reams of documents that haven't been translated yet. One thing about dictatorships, they keep good records.
The real reason behind the Dems opposition to the Iraq War lies buried in those documents that have yet to be translated. Notice how quickly the Dems jumped on an alleged security breach to have the document website shut down. And of course Negroponte was more than willing to comply.