diff --git a/htdocs/societe/class/api_thirdparties.class.php b/htdocs/societe/class/api_thirdparties.class.php
index 9a572a7e06f..a8b534f737a 100644
--- a/htdocs/societe/class/api_thirdparties.class.php
+++ b/htdocs/societe/class/api_thirdparties.class.php
@@ -1850,8 +1850,11 @@ class Thirdparties extends DolibarrApi
         if (!DolibarrApiAccess::$user->rights->societe->lire) {
             throw new RestException(401);
         }
-
-        $result = $this->company->fetch($rowid, $ref, $ref_ext, $barcode, $idprof1, $idprof2, $idprof3, $idprof4, $idprof5, $idprof6, $email, $ref_alias);
+		if ($rowid == 0) {
+			$result = $this->company->initAsSpecimen();
+		} else {
+			$result = $this->company->fetch($rowid, $ref, $ref_ext, $barcode, $idprof1, $idprof2, $idprof3, $idprof4, $idprof5, $idprof6, $email, $ref_alias);
+		}
         if (!$result) {
             throw new RestException(404, 'Thirdparty not found');
         }
diff --git a/htdocs/societe/class/societe.class.php b/htdocs/societe/class/societe.class.php
index 3fcc7e610ac..bb764f074f1 100644
--- a/htdocs/societe/class/societe.class.php
+++ b/htdocs/societe/class/societe.class.php
@@ -3774,6 +3774,7 @@ class Societe extends CommonObject
 
 		// Initialize parameters
 		$this->id = 0;
+		$this->entity = 1;
 		$this->name = 'THIRDPARTY SPECIMEN '.dol_print_date($now, 'dayhourlog');
 		$this->nom = $this->name; // For backward compatibility
 		$this->ref_ext = 'Ref ext';