diff --git a/cmake-utils/utils.cmake b/cmake-utils/utils.cmake
index c697332f..85f31802 100644
--- a/cmake-utils/utils.cmake
+++ b/cmake-utils/utils.cmake
@@ -12,11 +12,11 @@ function(target_activate_cpp14 TARGET)
     else("${CMAKE_VERSION}" VERSION_GREATER "3.1")
         check_cxx_compiler_flag("-std=c++14" COMPILER_HAS_CPP14_SUPPORT)
         if (COMPILER_HAS_CPP14_SUPPORT)
-            target_compile_options(${TARGET} PUBLIC -std=c++14)
+            target_compile_options(${TARGET} PRIVATE -std=c++14)
         else(COMPILER_HAS_CPP14_SUPPORT)
             check_cxx_compiler_flag("-std=c++1y" COMPILER_HAS_CPP14_PARTIAL_SUPPORT)
             if (COMPILER_HAS_CPP14_PARTIAL_SUPPORT)
-                target_compile_options(${TARGET} PUBLIC -std=c++1y)
+                target_compile_options(${TARGET} PRIVATE -std=c++1y)
             else()
                 message(FATAL_ERROR "Compiler doesn't support C++14")
             endif()