Contract Italy: better to keep the German contract?

Ciao tutti,
for the postmerger integration of our new daughter company I was send to Italy - with my German contract.
As I consider to stay longer in Italy (ca. 2 yrs) - I 'd need some information.
Should I keep my German contract or switch completely to the Italian company and accept an Italian contract.
Up to now everything is open - just want to be prepared.
Thanks a lot!!
Ciao, Caroline