diff --git a/nix/frama-c.nix b/nix/frama-c.nix
index aa1ac64409e8b8a22e4b2629e12f0b6568856d11..b66c80fe071bff6bb857128dbb3b8d29742c838c 100644
--- a/nix/frama-c.nix
+++ b/nix/frama-c.nix
@@ -43,6 +43,7 @@
 , dos2unix
 , doxygen
 , python3
+, python3Packages
 , release_mode ? false
 }:
 
@@ -101,6 +102,7 @@ stdenvNoCC.mkDerivation rec {
     dos2unix
     doxygen
     python3
+    python3Packages.pyaml
   ];
 
   outputs = [ "out" "build_dir" ];
diff --git a/nix/internal-tests.nix b/nix/internal-tests.nix
index 4bbf098618c4190ee55bcdfb908355c15c3fafc2..840f871f0a092861dc6dcc6384b9c69feee977db 100644
--- a/nix/internal-tests.nix
+++ b/nix/internal-tests.nix
@@ -47,6 +47,7 @@
 , perl
 , pkgs
 , python3
+, python3Packages
 , swiProlog
 , time
 , wp-cache
@@ -107,6 +108,7 @@ stdenvNoCC.mkDerivation rec {
     perl
     pkgs.getopt
     python3
+    python3Packages.pyaml
     swiProlog
     time
   ];