Based on your information, I guess you got the refugee status granted from the Federal Office for Migration and Refugees.
In this case, your residence permit is to be extended if the former decision of the Federal Office is not evoked. It should be noted that the responsible Immigration Authority - in case of low integration performance (e.g. no participation in the integration course) - can ask the Federal Office to check the revocation of the recognitaion of refugee status. It is therefore safer for you to attend the integration course in the longer term.