Edit in JSFiddle

function go() {
		var map = L.map("map").setView([48.845, 2.424], 5);
    var lyrOSM= L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png?') ;
        
    
    var lyrOrtho = L.geoportalLayer.WMTS({
        layer: "ORTHOIMAGERY.ORTHOPHOTOS",
    });
    var lyrMaps = L.geoportalLayer.WMTS({
        layer: "GEOGRAPHICALGRIDSYSTEMS.PLANIGNV2",
    }, { // leafletParams
        opacity: 0.7
    });

    map.addLayer(lyrOrtho);
    map.addLayer(lyrOSM) ;
    map.addLayer(lyrMaps) ;
    
    // Ajout des layers cercles de la zone de butinage
    var latitude = "48.845";
    var longitude = "2.424";
    var cercle_3000 = L.circle(
      [latitude, longitude],{
        radius: 3000, 
        color: "#C02900",
        weight: 1,
        opacity: 1,
        fillColor: "#FFFFFF",
        fillOpacity: 0.1
      }).addTo(map);
    
    
    var layerSwitcher = L.geoportalControl.LayerSwitcher({
    	layers : [{
        	layer : lyrOSM,
            config : {
            	title : "OSM",
                description : "Couche Open Street Maps"
            }
        }]
    });
	map.addControl(layerSwitcher);

}

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

var infoDiv= document.getElementById("info") ;
infoDiv.innerHTML= "<p> Extension Leaflet version "+Gp.leafletExtVersion+" ("+Gp.leafletExtDate+")</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;
}