google-maps - One zip code for several places/towns

Question

I use GMap places library's autocomplete feature like this :

var autoc = new google.maps.places.Autocomplete(input, {componentRestrictions: {country: 'fr'}});

I type zipcode and it gives suggestions, all is fine. But in France, one zip code can be used by several towns. It seems GMap proposes only one place for each zip code. Is it a known issue?

Any idea to counter this?

Thanks.