It worked ! but additionally to the steps described above I had to add camembert to the dict MAX_SEQUENCE_LENGTHS in rasa/nlu/utils/hugging_face.py
MAX_SEQUENCE_LENGTHS = { “camembert”: 512, “bert”: 512, “gpt”: 512, “gpt2”: 512, “xlnet”: NO_LENGTH_RESTRICTION, “distilbert”: 512, “roberta”: 512, }