Detect blog language?

On my multilingual, multisite setup I’m trying to have multiple single.php, based on which blog it is destined to. My idea, based on a trick I found here on these forums, was to do something a little bit like the code pasted down here, but it won’t work (no matter the ICL language I try it on, it always give me the “else” one).

<?php
$post = $wp_query->post;
if (get_locale() = 'fr') { include (TEMPLATEPATH . '/single-fr.php');
}
else { include (TEMPLATEPATH . '/single-other.php');
}
?>

Is there any other way I could detect the language of the current site? Any idea how to make this work?