Elasticsearch snowball in French not stemming correctly

Question

I've seen a problem with the same stem word in French.

Here is an example: snowball in French

or

curl -XDELETE http://localhost:9200/stacko36088193
curl -XPOST http://localhost:9200/stacko36088193 -d '
{
  "index": {
    "number_of_shards": 1,
    "analysis": {
      "analyzer": {
        "my_analyzer": {
          "type": "snowball",
          "language" : "French"
        }
      }
    }
  }
}'
curl 'localhost:9200/stacko36088193/_analyze?pretty=1&analyzer=my_analyzer' -d 'développeur développeuse'

And see token keys

{
  "tokens" : [ {
    "token" : "développeur",
    "start_offset" : 0,
    "end_offset" : 11,
    "type" : "<ALPHANUM>",
    "position" : 1
  }, {
    "token" : "développ",
    "start_offset" : 12,
    "end_offset" : 24,
    "type" : "<ALPHANUM>",
    "position" : 2
  } ]
}

How can you do to have the same stem for all of these words?