This is a very simple approach to build a Homematic IP to mqtt-smarthome bridge.
I've tested this script only with an HmIP-MOD-OC8 module. There might be some issue for other devices, especially with integer/float values (see here).
docker run -d --restart=always --name=hmip \
-p 3126:3126 \
dersimn/simplehmip2mqtt \
--ccu-address 10.1.1.112 \
--init-address 10.1.1.50 \
--mqtt-url mqtt://10.1.1.50 \
--filter-blacklist "^PARTY_"