Lua法国语言环境失败了

Question

我试过这段代码：

assert(os.setlocale('fr_FR'))
print(12.34)

它失败了。

locale.lua 
lua: locale.lua:1: assertion failed!
stack traceback:
    [C]: in function 'assert'
    locale.lua:1: in main chunk
    [C]: in ?

在Ubuntu 14.04上，lua -v

Lua 5.2.3  Copyright (C) 1994-2013 Lua.org, PUC-Rio