diff --git a/src/features/grid/api/get-product-rows.ts b/src/features/grid/api/get-product-rows.ts
index 85cc304..73063cd 100644
--- a/src/features/grid/api/get-product-rows.ts
+++ b/src/features/grid/api/get-product-rows.ts
@@ -34,28 +34,36 @@ export async function getProductRows(input: GetProductRowsInput): Promise<Produc
             )
         );
 
-    // Group by codein and aggregate monthly sales
+    // Group by codein and aggregate monthly sales + track store participation
     const productMap = new Map<string, ProductRow>();
+    const storeParticipationMap = new Map<string, Map<string, Set<string>>>(); // codein -> magasin -> Set of periods
 
     for (const row of rows) {
         // Ignorer les données qui ne font pas partie des 12 mois complets
         if (!allowedPeriods.has(row.periode)) continue;
 
-        const existing = productMap.get(row.codein);
-        const monthKey = row.periode;
+        const { codein, magasin, periode } = row;
+
+        // Suivi de la participation par magasin
+        if (!storeParticipationMap.has(codein)) storeParticipationMap.set(codein, new Map());
+        const productStores = storeParticipationMap.get(codein)!;
+        if (!productStores.has(magasin)) productStores.set(magasin, new Set());
+        productStores.get(magasin)!.add(periode);
+
+        const existing = productMap.get(codein);
         const qty = Math.abs(parseFloat(row.quantite?.toString() ?? "0"));
         const ca = Math.abs(parseFloat(row.montantMvt?.toString() ?? "0"));
         const marge = Math.abs(parseFloat(row.margeMvt?.toString() ?? "0"));
 
         if (existing) {
-            existing.sales12m[monthKey] = (existing.sales12m[monthKey] ?? 0) + qty;
+            existing.sales12m[periode] = (existing.sales12m[periode] ?? 0) + qty;
             existing.totalQuantite += qty;
             existing.totalCa += ca;
             existing.totalMarge += marge;
             existing.tauxMarge = existing.totalCa > 0 ? (existing.totalMarge / existing.totalCa) * 100 : 0;
         } else {
-            productMap.set(row.codein, {
-                codein: row.codein,
+            productMap.set(codein, {
+                codein,
                 codeFournisseur: row.codeFournisseur ?? "",
                 nomFournisseur: row.nomFournisseur ?? "",
                 libelle1: row.libelle1 ?? "",
@@ -65,16 +73,32 @@ export async function getProductRows(input: GetProductRowsInput): Promise<Produc
                 libelle3: row.libelle3 ?? "",
                 codeGamme: (row.codeGamme as GammeCode | null),
                 codeGammeDraft: null,
-                sales12m: { [monthKey]: qty },
+                sales12m: { [periode]: qty },
                 totalQuantite: qty,
                 totalCa: ca,
                 totalMarge: marge,
                 tauxMarge: ca > 0 ? (marge / ca) * 100 : 0,
                 score: 0,
+                workingStores: [],
                 aiRecommendation: null,
             });
         }
     }
 
+    // Finaliser la liste des magasins "actifs" (travaillant le produit : >= 3 mois de vente)
+    for (const [codein, product] of productMap.entries()) {
+        const productStores = storeParticipationMap.get(codein);
+        if (productStores) {
+            const workingStores: string[] = [];
+            for (const [magasin, periods] of productStores.entries()) {
+                if (magasin === "TOTAL") continue;
+                if (periods.size >= 3) {
+                    workingStores.push(magasin);
+                }
+            }
+            product.workingStores = workingStores.sort();
+        }
+    }
+
     return computeProductScores(Array.from(productMap.values()));
 }
diff --git a/src/features/grid/components/heatmap-grid.tsx b/src/features/grid/components/heatmap-grid.tsx
index 905a6e9..9c2d03c 100644
--- a/src/features/grid/components/heatmap-grid.tsx
+++ b/src/features/grid/components/heatmap-grid.tsx
@@ -127,10 +127,29 @@ export function HeatmapGrid({ onSelectionChange }: HeatmapGridProps) {
             accessorKey: "libelle1",
             header: "Désignation",
             size: 280,
-            cell: ({ getValue }) => (
-                <span className="text-[13px] font-bold truncate block max-w-[270px]" title={getValue<string>()} style={{ color: "var(--text-primary)" }}>
-                    {getValue<string>()}
-                </span>
+            cell: ({ row }) => (
+                <div className="flex items-center gap-2 overflow-hidden w-full pr-1">
+                    <span className="text-[13px] font-bold truncate flex-1" title={row.original.libelle1} style={{ color: "var(--text-primary)" }}>
+                        {row.original.libelle1}
+                    </span>
+                    <div className="flex gap-1 shrink-0">
+                        {row.original.workingStores.map((magasin) => (
+                            <div
+                                key={magasin}
+                                title={`Travaillé par : ${magasin}`}
+                                className="w-4 h-4 rounded-full flex items-center justify-center text-[10px] font-black border"
+                                style={{
+                                    background: "var(--bg-elevated)",
+                                    borderColor: "var(--border-strong)",
+                                    color: "var(--text-secondary)",
+                                    boxShadow: "var(--shadow-xs)"
+                                }}
+                            >
+                                {magasin.charAt(0).toUpperCase()}
+                            </div>
+                        ))}
+                    </div>
+                </div>
             ),
         },
         {
diff --git a/src/types/grid.ts b/src/types/grid.ts
index ac1f31f..e0f80bc 100644
--- a/src/types/grid.ts
+++ b/src/types/grid.ts
@@ -49,6 +49,7 @@ export interface ProductRow {
     tauxMarge: number;
     /** Combined performance score (0-10) */
     score: number;
+    workingStores: string[];
     aiRecommendation?: string | null;
 }