Edit in JSFiddle

function go() {
    var map = new ol.Map({
        target: 'map',
        layers: [
            new ol.layer.Tile({
				source: new ol.source.GeoportalWMTS({
					layer: "ORTHOIMAGERY.ORTHOPHOTOS",
				}),
				opacity: 0.7
			})
        ],
        view: new ol.View({
            center: [2,48],
            zoom: 12,
            projection : "IGNF:RGF93G",
            resolutions : [1.40625,0.703125,0.3515625,0.17578125,0.087890625,0.0439453125,0.02197265625,0.010986328125,0.0054931640625,0.00274658203125,0.001373291015625,0.0006866455078125,0.00034332275390625,0.000171661376953126,0.0000858306884765628,0.0000429153442382813,0.0000214576721191407,0.0000107288360595703,0.00000536441802978517,0.00000268220901489259,0.0000013411045074463,0.000000670552253723145,0.00000033527612686157]
        })
    });
}

Gp.Services.getConfig({
    apiKey: "jhyvi0fgmnuxvfv0zjzorvdn",
    onSuccess: go
});

var infoDiv= document.getElementById("info") ;
infoDiv.innerHTML= "<p> Extension OL3 version "+Gp.ol3extVersion+" ("+Gp.ol3extDate+")</p>" ;

<div id="map"></div>
<div id="info"></div>

#map {
    padding: 5px;
    width: 100%;
    height: 300px;
    box-shadow: 0 0 10px #999;
}
#info {
    padding: 5px;
    width: 100%;
    height: 20px;
    font-family : "monospace" ;
    font-size: 10px;
}