diff --git a/core/class/declarationtva.class.php b/core/class/declarationtva.class.php
index ebe2513..0e3983e 100644
--- a/core/class/declarationtva.class.php
+++ b/core/class/declarationtva.class.php
@@ -284,6 +284,9 @@ class DeclarationTVA
         // Calculate line 16: Subtotal of lines 08, 09, 9B (for user reference)
         $this->calculateLine16($declaration_id);
         
+        // Calculate line 23: Subtotal of lines 20, 21, 22 (for user reference)
+        $this->calculateLine23($declaration_id);
+        
         // Calculate D-section result lines (25, 26, 28, 29)
         $this->calculateDSectionLines($declaration_id, $total_vat_collected, $total_vat_deductible);
 
@@ -332,6 +335,40 @@ class DeclarationTVA
         return true;
     }
 
+    /**
+     * Calculate line 23: Subtotal of lines 20, 21, 22 (for user reference)
+     *
+     * @param int $declaration_id Declaration ID
+     * @return bool Success
+     */
+    private function calculateLine23($declaration_id)
+    {
+        // Get the amounts from lines 20, 21, 22
+        $sql = "SELECT ca3_line, vat_amount FROM " . MAIN_DB_PREFIX . "declarationtva_ca3_lines 
+                WHERE declaration_id = " . (int)$declaration_id . " 
+                AND ca3_line IN ('20', '21', '22')";
+        
+        $result = $this->db->query($sql);
+        $line_23_total = 0;
+        $account_labels = array();
+        
+        if ($result) {
+            while ($obj = $this->db->fetch_object($result)) {
+                $line_23_total += $obj->vat_amount;
+                $account_labels[] = "Line " . $obj->ca3_line . ": " . number_format($obj->vat_amount, 2);
+            }
+        }
+        
+        // Create line 23 record
+        $this->createCA3Line($declaration_id, '23', 'Subtotal: ' . implode(', ', $account_labels), array(
+            'base_amount' => 0,
+            'vat_amount' => $line_23_total,
+            'total_amount' => $line_23_total
+        ));
+        
+        return true;
+    }
+
     /**
      * Calculate D-section result lines (25, 26, 28, 29)
      *
diff --git a/declarationtva_view.php b/declarationtva_view.php
index 9e0b538..0a92a83 100644
--- a/declarationtva_view.php
+++ b/declarationtva_view.php
@@ -243,6 +243,14 @@ foreach ($section_c_lines as $line) {
     print '</tr>';
 }
 
+// Line 23: Subtotal (calculated automatically)
+$data = isset($ca3_data['23']) ? $ca3_data['23'] : array('line_label' => '', 'vat_amount' => 0);
+print '<tr class="pair">';
+print '<td><strong>23</strong></td>';
+print '<td colspan="2"><strong>Sous-total TVA déductible (20 + 21 + 22)</strong></td>';
+print '<td class="right"><strong>' . price($data['vat_amount']) . '</strong></td>';
+print '</tr>';
+
 // Section D: Résultat
 print '<tr class="liste_titre">';
 print '<td colspan="4"><strong>D. ' . $langs->trans("CA3SectionD") . '</strong></td>';