diff --git a/gnu/packages/protobuf.scm b/gnu/packages/protobuf.scm
index ab701b254d..b580f8b2a7 100644
--- a/gnu/packages/protobuf.scm
+++ b/gnu/packages/protobuf.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2022 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2016 Daniel Pimentel <d4n1@d4n1.org>
 ;;; Copyright © 2016 Leo Famulari <leo@famulari.name>
 ;;; Copyright © 2017, 2018, 2019, 2022 Ricardo Wurmus <rekado@elephly.net>
@@ -468,9 +468,8 @@ (define-public python-protobuf-3.6
        (sha256
         (base32
          "04bqb12smlckzmgkj6vgmpbr3cby0n6726cmz33bqr7kn1vb728l"))))
-    (inputs
-     (cons python-six
-           (package-inputs python-protobuf)))))
+    (arguments '())                            ;no "--cpp_implementation" here
+    (inputs (list python-six))))
 
 (define-public python-proto-plus
   (package