diff --git a/CMakeLists.txt b/CMakeLists.txt
index c502a6a7e..d82e31228 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -96,6 +96,10 @@ if(GTSAM_INSTALL_MATLAB_TOOLBOX AND GTSAM_TYPEDEF_POINTS_TO_VECTORS)
     message(FATAL_ERROR "GTSAM_INSTALL_MATLAB_TOOLBOX and GTSAM_TYPEDEF_POINTS_TO_VECTORS are both enabled. For now, the MATLAB toolbox cannot deal with this yet.  Please turn one of the two options off.")
 endif()
 
+if(GTSAM_INSTALL_CYTHON_TOOLBOX AND GTSAM_TYPEDEF_POINTS_TO_VECTORS)
+    message(FATAL_ERROR "GTSAM_INSTALL_CYTHON_TOOLBOX and GTSAM_TYPEDEF_POINTS_TO_VECTORS are both enabled. For now, the CYTHON toolbox cannot deal with this yet.  Please turn one of the two options off.")
+endif()
+
 # Flags for choosing default packaging tools
 set(CPACK_SOURCE_GENERATOR "TGZ" CACHE STRING "CPack Default Source Generator")
 set(CPACK_GENERATOR        "TGZ" CACHE STRING "CPack Default Binary Generator")