diff --git a/targets/TARGET_STM/TARGET_STM32G4/TARGET_STM32G431xB/CMakeLists.txt b/targets/TARGET_STM/TARGET_STM32G4/TARGET_STM32G431xB/CMakeLists.txt
index b34369cf75..48b11b5b21 100644
--- a/targets/TARGET_STM/TARGET_STM32G4/TARGET_STM32G431xB/CMakeLists.txt
+++ b/targets/TARGET_STM/TARGET_STM32G4/TARGET_STM32G431xB/CMakeLists.txt
@@ -17,7 +17,7 @@ set_property(GLOBAL PROPERTY MBED_TARGET_LINKER_FILE ${CMAKE_CURRENT_SOURCE_DIR}
 
 target_sources(mbed-core
     INTERFACE
-    	system_clock.c
+        system_clock.c
         ${STARTUP_FILE}
 )