Edit in JSFiddle

function go() {
    var cartesLyr = new ol.layer.GeoportalWMTS({
                layer: "GEOGRAPHICALGRIDSYSTEMS.PLANIGNV2",
            }) ;
    var map = new ol.Map({
        target: 'map',
        layers: [
            cartesLyr
        ],
        view: new ol.View({
            center: [288074.8449901076, 6247982.515792289],
            zoom: 12
        })
    });    
    var searchControl = new ol.control.SearchEngine({
        // additionnal options may be specified here
    });
    map.addControl(searchControl);
}

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

var infoDiv = document.getElementById("info");
infoDiv.innerHTML = "<p> Extension OL version " + Gp.olExtVersion + " (" + Gp.olExtDate + ")</p>";

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

#map {
    padding: 5px;
    width: 100%;
    height: 600px;
    box-shadow: 0 0 10px #999;
}

#info {
    padding: 5px;
    width: 100%;
    height: 20px;
    font-family: "monospace";
    font-size: 10px;
}