diff --git a/Framework/Particles/CMakeLists.txt b/Framework/Particles/CMakeLists.txt
index 7798d2226c7fd70a48fa452975cceb27eb71da35..cde894b095905f226a8e3a781bcc9f3b0daeb896 100644
--- a/Framework/Particles/CMakeLists.txt
+++ b/Framework/Particles/CMakeLists.txt
@@ -1,3 +1,5 @@
+set(Python_ADDITIONAL_VERSIONS 3)
+find_package(PythonInterp 3 REQUIRED)
 
 add_custom_command (
   OUTPUT  ${PROJECT_BINARY_DIR}/Framework/Particles/GeneratedParticleProperties.inc
diff --git a/Processes/Sibyll/CMakeLists.txt b/Processes/Sibyll/CMakeLists.txt
index 24e5fffc2054bd0146d698ac102cd0f88cc0e19d..880496a219b8674a2cca984c6ab3e8615ecd1470 100644
--- a/Processes/Sibyll/CMakeLists.txt
+++ b/Processes/Sibyll/CMakeLists.txt
@@ -1,3 +1,6 @@
+set(Python_ADDITIONAL_VERSIONS 3)
+find_package(PythonInterp 3 REQUIRED)
+
 add_custom_command (
   OUTPUT  ${PROJECT_BINARY_DIR}/Processes/Sibyll/Generated.inc
   COMMAND ${PROJECT_SOURCE_DIR}/Processes/Sibyll/code_generator.py