CartoDB TileJSON in mapbox.js courtesy of @andrewxhill

<!DOCTYPE html>
<html>
<head>
  <script src='https://api.tiles.mapbox.com/mapbox.js/v0.6.7/mapbox.js'></script>
  <link href='https://api.tiles.mapbox.com/mapbox.js/v0.6.7/mapbox.css' rel='stylesheet' />
  <style>
    body { margin:0; padding:0; }
    #map { position:absolute; top:0; bottom:0; width:100%; }
  </style>
</head>
<body>
<div id='map'>
</div>
<script>
var m = mapbox.map('map');
 
//Define CartoDB tilejson
var communes = mapbox.layer().tilejson({ 
        version: '1.0.0', 
        scheme: 'xyz', 
        tiles: ['https://dai.cartodb.com/tiles/ag_2011_commune3/{z}/{x}/{y}.png'],
        grids: ['https://dai.cartodb.com/tiles/ag_2011_commune3/{z}/{x}/{y}.grid.json'] 
    }); 
 
//Add layers to map
m.addLayer(new MM.TemplatedLayer('https://b.tile.stamen.com/toner/{Z}/{X}/{Y}.png'));
m.addLayer(communes);
 
m.ui.attribution.add()
    .content('Map tiles by <a href="https://stamen.com">Stamen Design</a>, under' +
    ' <a href="https://creativecommons.org/licenses/by/3.0">CC BY 3.0</a>.' +
    ' Data by <a href="https://openstreetmap.org">OpenStreetMap</a>, under <a href="https://creativecommons.org/licenses/by-sa/3.0">CC BY SA</a>.');
m.ui.zoomer.add();
m.ui.zoombox.add();
m.zoom(3);
</script>
</body>
</html>

Modified http://api.tiles.mapbox.com/mapbox.js/v0.6.7/mapbox.js to a secure url

https://api.tiles.mapbox.com/mapbox.js/v0.6.7/mapbox.js