On 17 June , Grouchy was unable to close with the Prussians .
Napoleon sent Grouchy to pursue a part of the retreating Prussian army under the command of General Johann von Thielmann .
On 17 June , Grouchy was unable to close with the Prussian .
Napoleon sent Grouchy to pursue a part of the retreating Prussian army under the command of General Johann von Thielmann .