diff --git a/htdocs/core/modules/import/import_csv.modules.php b/htdocs/core/modules/import/import_csv.modules.php
index 781c22ce7e3..7d535520496 100644
--- a/htdocs/core/modules/import/import_csv.modules.php
+++ b/htdocs/core/modules/import/import_csv.modules.php
@@ -716,6 +716,8 @@ class ImportCsv extends ModeleImports
 				}
 
 				// We add hidden fields (but only if there is at least one field to add into table)
+				// We process here all the fields that were declared into the array ->import_fieldshidden_array of the descriptor file.
+				// Previously we processed the ->import_fields_array.
 				if (!empty($listfields) && is_array($objimport->array_import_fieldshidden[0])) {
 					// Loop on each hidden fields to add them into listfields/listvalues
 					foreach ($objimport->array_import_fieldshidden[0] as $key => $val) {
diff --git a/htdocs/core/modules/import/import_xlsx.modules.php b/htdocs/core/modules/import/import_xlsx.modules.php
index 1c38f52cbfc..0effa87cb3c 100644
--- a/htdocs/core/modules/import/import_xlsx.modules.php
+++ b/htdocs/core/modules/import/import_xlsx.modules.php
@@ -757,6 +757,8 @@ class ImportXlsx extends ModeleImports
 				}
 
 				// We add hidden fields (but only if there is at least one field to add into table)
+				// We process here all the fields that were declared into the array $this->import_fieldshidden_array of the descriptor file.
+				// Previously we processed the ->import_fields_array.
 				if (!empty($listfields) && is_array($objimport->array_import_fieldshidden[0])) {
 					// Loop on each hidden fields to add them into listfields/listvalues
 					foreach ($objimport->array_import_fieldshidden[0] as $key => $val) {