Elasticsearch match containg Umlaut does not work

I have the following query:

res = es.search(index="index", body={"query": {
    "bool" : {
        "must" : {
            "match" : { "text" : "Flüchtl*" }
        },
        "filter": {
            "range" : { "publish_date" : {"gte": "2015-08-30 00:00:00", "lt": "2016-01-01 00:00:00"}
            }
        }
    }
}}, size=10000)

When I do this query in Kibana, I get 3071 results, however when I do this with the Python library, I get zero results. When I use words that do not contain Umlaute, everything works fine. What am I doing wrong?