The official way of saying numbers in French is to spell each digit separately and 1 is "unité". So 011 is zéro, unité, unité. However if it is clear enough an

The official way of saying numbers in French is to spell each digit separately and 1 is "unité". So 011 is zéro, unité, unité. However if it is clear enough and there is no ambiguity, the common way of saying numbers can be used, so zéro onze is acceptable. In normal conditions, no french speaker will mistake "onze" for "un", the latter should be "unité" anyways. The main problem with "un" is that it sounds like "hein?", which means something like "huh?", the kind of meaningless words that punctuate conversations without even noticing.