diff --git a/CMakeLists.txt b/CMakeLists.txt
index ba6cd2d9..031971af 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -394,24 +394,32 @@ if(PORTABLE OR (PLATFORM_WINDOWS AND MXE))
     # We need to use STRING because PATH doesn't accept relative paths
     set(COLOBOT_INSTALL_BIN_DIR ./ CACHE STRING "Colobot binary directory")
     set(COLOBOT_INSTALL_LIB_DIR ./ CACHE STRING "Colobot libraries directory")
+    set(COLOBOT_RELATIVE_DATA_DIR data CACHE STRING "Colobot shared data directory (relative)")
+    set(COLOBOT_RELATIVE_I18N_DIR lang CACHE STRING "Colobot translations directory (relative)")
     set(COLOBOT_INSTALL_DATA_DIR ./data CACHE STRING "Colobot shared data directory")
     set(COLOBOT_INSTALL_I18N_DIR ./lang CACHE STRING "Colobot translations directory")
     set(COLOBOT_INSTALL_DOC_DIR ./doc CACHE STRING "Colobot documentation directory")
 elseif(PLATFORM_WINDOWS)
     set(COLOBOT_INSTALL_BIN_DIR ${CMAKE_INSTALL_PREFIX}/ CACHE PATH "Colobot binary directory")
     set(COLOBOT_INSTALL_LIB_DIR ${CMAKE_INSTALL_PREFIX}/ CACHE PATH "Colobot libraries directory")
+    set(COLOBOT_RELATIVE_DATA_DIR data CACHE STRING "Colobot shared data directory (relative)")
+    set(COLOBOT_RELATIVE_I18N_DIR lang CACHE STRING "Colobot translations directory (relative)")
     set(COLOBOT_INSTALL_DATA_DIR ${CMAKE_INSTALL_PREFIX}/data CACHE PATH "Colobot shared data directory")
     set(COLOBOT_INSTALL_I18N_DIR ${CMAKE_INSTALL_PREFIX}/lang CACHE PATH "Colobot translations directory")
     set(COLOBOT_INSTALL_DOC_DIR ${CMAKE_INSTALL_PREFIX}/doc CACHE PATH "Colobot documentation directory")
 elseif(PLATFORM_MACOSX)
     set(COLOBOT_INSTALL_BIN_DIR ../MacOS CACHE STRING "Colobot binary directory")
     set(COLOBOT_INSTALL_LIB_DIR ../MacOS CACHE STRING "Colobot libraries directory")
+    set(COLOBOT_RELATIVE_DATA_DIR . CACHE STRING "Colobot shared data directory (relative)")
+    set(COLOBOT_RELATIVE_I18N_DIR i18n CACHE STRING "Colobot translations directory (relative)")
     set(COLOBOT_INSTALL_DATA_DIR . CACHE STRING "Colobot shared data directory")
     set(COLOBOT_INSTALL_I18N_DIR i18n CACHE SRING "Colobot translations directory")
     set(COLOBOT_INSTALL_DOC_DIR doc CACHE STRING "Colobot documentation directory")
 else()
     set(COLOBOT_INSTALL_BIN_DIR ${CMAKE_INSTALL_PREFIX}/games CACHE PATH "Colobot binary directory")
     set(COLOBOT_INSTALL_LIB_DIR ${CMAKE_INSTALL_PREFIX}/lib/colobot CACHE PATH "Colobot libraries directory")
+    set(COLOBOT_RELATIVE_DATA_DIR ../share/games/colobot CACHE STRING "Colobot shared data directory (relative)")
+    set(COLOBOT_RELATIVE_I18N_DIR ../share/locale CACHE STRING "Colobot translations directory (relative)")
     set(COLOBOT_INSTALL_DATA_DIR ${CMAKE_INSTALL_PREFIX}/share/games/colobot CACHE PATH "Colobot shared data directory")
     set(COLOBOT_INSTALL_I18N_DIR ${CMAKE_INSTALL_PREFIX}/share/locale CACHE PATH "Colobot translations directory")
     set(COLOBOT_INSTALL_DOC_DIR ${CMAKE_INSTALL_PREFIX}/share/doc/colobot CACHE PATH "Colobot documentation directory")
diff --git a/src/common/config.h.cmake b/src/common/config.h.cmake
index f6d0bcae..6100d7dc 100644
--- a/src/common/config.h.cmake
+++ b/src/common/config.h.cmake
@@ -18,5 +18,5 @@
 
 #cmakedefine PORTABLE_SAVES @PORTABLE_SAVES@
 
-#define COLOBOT_DEFAULT_DATADIR "@COLOBOT_INSTALL_DATA_DIR@"
-#define COLOBOT_I18N_DIR "@COLOBOT_INSTALL_I18N_DIR@"
+#define COLOBOT_DEFAULT_DATADIR "@COLOBOT_RELATIVE_DATA_DIR@"
+#define COLOBOT_I18N_DIR "@COLOBOT_RELATIVE_I18N_DIR@"
diff --git a/src/common/system/system.cpp b/src/common/system/system.cpp
index 12dc1d36..efec405b 100644
--- a/src/common/system/system.cpp
+++ b/src/common/system/system.cpp
@@ -36,6 +36,7 @@
 #include <iostream>
 #include <algorithm>
 
+#include <physfs.h>
 
 std::unique_ptr<CSystemUtils> CSystemUtils::Create()
 {
@@ -178,12 +179,12 @@ float CSystemUtils::TimeStampDiff(SystemTimeStamp *before, SystemTimeStamp *afte
 
 std::string CSystemUtils::GetDataPath()
 {
-    return COLOBOT_DEFAULT_DATADIR;
+    return std::string{PHYSFS_getBaseDir()} + COLOBOT_DEFAULT_DATADIR;
 }
 
 std::string CSystemUtils::GetLangPath()
 {
-    return COLOBOT_I18N_DIR;
+    return std::string{PHYSFS_getBaseDir()} + COLOBOT_I18N_DIR;
 }
 
 std::string CSystemUtils::GetSaveDir()