The 'Battle of Lagarde' was fought between German and expatriate Polish forces near Lagarde in the Moselle river area during the German 'Gelb' invasion of France (17/18 June 1940).

In this battle, the Polish 1^st Grenadiers Division, commanded by Generał brygady Bolesław Bronisław Duch, clashed with elements of General Walter Schroth’s XII Corps of Generaloberst Erwin von Witzleben’s 1^st Army within Generaloberst Wilhelm Ritter von Leeb’s Heeresgruppe 'C'.

The 1^st Grenadiers Division (1ère Division des Grenadiers in French) was a Polish infantry formation which had been raised in France during the 'Phoney War'. The division was created as a part of the Polish Army in France on the basis of Poles already in France. As a result of the Franco-Polish alliance, the formation of a Polish division in France began early in September 1939. The French government allocated the military camp at Coëtquidan to the Polish military mission and permitted voluntary recruitment from Poles already in France and who were particularly numerous in the coal-producing regions of Flanders. After the fall of Poland and the formation of the Polish government-in-exile, the newly appointed Polish commander-in-chief, Generał dywizji Władysław Sikorsky, ordered the formation of the 1^st Grenadier Division on 13 November 1939. Initially commanded by Pułkownik Stanisław Maczek, the division was taken over by Pułkownik (from 3 May 1940 Generał brygady) Bolesław Bronisław Duch in January 1940. The division was organised according to the French model, and was equipped with French weapons and uniforms. Altogether, the formation eventually numbered about 13,000 enlisted men, 2,600 non-commissioned and 580 commissioned officers when it was sworn in by Sikorsky on 25 May 1940, shortly before arriving at the front in Lorraine.

At the end of April 1940, the division was moved to Colombey-les-Belles in Lorraine where it received its long-awaited heavy equipment and final training. On 18 May, the formation was moved to the Sarre area and was part of the French XX Corps d’Armée, an element of General Edouard Réquin’s 4^th Armée. The 1^st Warsaw Grenadier Regiment under Pułkownik Lowczowski was assigned to defence of the 'Ligne Maginot' Line near Wittlesburg. Initially divided between the French corps' two sub-formations, 52ème Division d’Infanterie and the Secteur Fortifié de la Sarre, the division was tasked with a support role.

The division first saw combat on 14 June 1940, when it came under attack by German forces. The following day the division was concentrated and successfully defended its positions. However, during the night the 52ème Division d’Infanterie collapsed and withdrew, toward Dieuze, soon after it was attacked. Fearing his corps being cut in two, the formation commander ordered the Poles to withdraw to the second line of defence. It withdrew to the area of Dieuze, where it covered the retreat of the French division throughout 15/16 June. On 17 June the division was ordered to hold the line of the Marne-Rhine Canal in the sector between Lagarde and the Forêt de Rechicourt. On the same day, the first German units crossed the canal in the sector defended by the 2^nd Wielkopolska Grenadier Regiment, but were soon forced to abandon their positions. On 18 June Germans once again tried to cross the canal, but failed. At the same time, Generalleutnant Karl Strecker’s 79^th Division broke the French defence of the 52ème Division d’Infanterie, and the Polish formation was attacked from the left wing.

In the afternoon of 18 June, the Germans continued their advance. The Polish grenadiers, who had suffered losses amounting to as much as 50% of their strength, were replaced by French units and ordered to concentrate near Baccarat. Two days later, on 20 June, the Polish division occupied defensive positions along the Meurthe river near Raon l’Etape. After the French divisions located in this area had withdrawn, Duch decided to dissolve his division on 21 June, sending a coded message '4444' indicating 'The end of hostilities, the Division is dissolved. Safeguard the documents and the flags, destroy the equipment, break into small groups and tried to get to southern France and then to Britain'.