I finally found the correct code for the Icon.js file :
import L from 'leaflet';
const iconPerson = new L.Icon({
iconUrl: require('../img/marker-pin-person.svg'),
iconRetinaUrl: require('../img/marker-pin-person.svg'),
iconAnchor: null,
popupAnchor: null,
shadowUrl: null,
shadowSize: null,
shadowAnchor: null,
iconSize: new L.Point(60, 75),
className: 'leaflet-div-icon'
});
export { iconPerson };