diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 015f458a63..3749f84e21 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -3938,21 +3938,23 @@ tramp-handle-make-process
 		       (when (string-match-p "=" elt) elt))
 		     tramp-remote-process-environment))
 	       ;; We use as environment the difference to toplevel
 	       ;; `process-environment'.
 	       (env (dolist (elt process-environment env)
 		      (when
 			  (and
 			   (string-match-p "=" elt)
 			   (not
 			    (member
-			     elt (default-toplevel-value 'process-environment))))
+			     elt (default-toplevel-value 'process-environment)))
+                           (not (member (car (split-string elt "="))
+                                        tramp-remote-process-environment)))
 			(setq env (cons elt env)))))
 	       (env (setenv-internal
 		     env "INSIDE_EMACS" (tramp-inside-emacs) 'keep))
 	       (env (mapcar #'tramp-shell-quote-argument (delq nil env)))
 	       ;; Quote command.
 	       (command (mapconcat #'tramp-shell-quote-argument command " "))
 	       ;; Set cwd and environment variables.
 	       (command
 	        (append `("cd" ,localname "&&" "(" "env") env `(,command ")"))))