>>9319327
Depends on the country. In some EU countries like Germany bosses are wired to eachother and call each other up. Atleast if it's in the same city. Atleast it's like that in the IT field. It's not unusual that your previous Boss or the HR sloots are gonna get a call from your potential new company and ask about you and your perfomances.
Plus letter of recommendations are sometimes a thing too; even though it's not relevant in your case since you were employed and already had your interview.
I would be silent about it. Best case it won't be investigated or no questions asked and they just ask when you can start. Getting fired seems like a red flag in the industry so it's nothing you should be toooo open about. If they ask, tell them politery the story that you have been fired for intern company reasons and all that. Don't go too much into detail