But if I go to Germany and with my Italian number I call a German number is that going to be considered roaming or it's going to be the same as the previous situation (call to German number from Italian number in Italy)?
Its a domestic call, as you are roaming within the EEA to another EEA destination and placing a call solely within the EEA country you are in:
Pursuant to Regulation (EU) No 531/2012, roaming providers should not levy any surcharge additional to the domestic retail price on roaming customers in any Member State, for any regulated roaming call made or received, any regulated roaming SMS message sent or any regulated data roaming service used, including MMS messages, subject to a ‘fair use policy’.
Phone calls, SMS and going online with your mobile device from another EU country will be covered in the national bundle. The minutes of calls, SMS and megabytes of data that a person consumes abroad (within the EU) will be charged the same as at home.
The EU "roam like at home" rules mean that when you use your mobile phone while travelling outside your home country in any EU country you don't have to pay any additional roaming charges. You benefit from these rules when calling (to mobile and fixed phones), sending text messages (SMS) and using data services while abroad.
You pay exactly the same price for using these services when travelling in the EU as you would if you were at home.
If you were to call the German number while in Italy, that is not considered a domestic call and would be charged at your providers international rate.
If you were to call the German number while in Germany, on an Italian SIM roaming to a German provider, then that is considered a domestic call and would be charged at your providers domestic rate.
If you were to call an Italian number while in Germany, on an Italian SIM roaming to a German provider, then that would be considered an international call and would be charged at your providers international rate.