I was playing a game as Victoria a couple of days back, and got attacked by a couple of galleonsworth of French units; Trebuchets, A few cavalry and some grenadiers. However, they all came from the galleon itself.

This happened on several occasions, not only from the french, but other civs too. I was doubtful they had the amphibious promotion, which was proven when some landed and (strangely) went back onto their galleon the next turn and attacked me from that. They didn't have the amphibious promotion.

Unfortunately, I played on and didn't keep the save. I guess this isn't intended.

The galleon is a safer place for them because you cannot attack the stack back from the town (if you don't have ships), so that's the natural place to launch the attack even without the necessary promotions.

Not that it doesn't look silly for three galleon-fulls of attackers to die attacking a single defending longbowman...

You don't need the promotion to do amphibious assaults, it only makes them more effective (i.e. no penalty).

Really? You can attack from a transport even without the promotion? I guess that explains Shaka's stack of a dozen catapults pounding my city from the sea... Here I was thinking he had just given amphibious promotions to all his siege weapons! I lost that city...

Speaking of which, can catapults even get amphibious?

I was also surprised by the attacks directly from ships. I think this wasn't possible in earlier versions, am I right? I would certainly like it more if you could only do it with amphibious units.

Just goes to show how blissfully unaware I am of game mechanics then!

Yeah - this isn't a bug. But it might be an AI issue (if they should land first to increase the chance of capturing the city)

Can you bombard a city with catapults directly from the ships? I never even contemplated the possibility, but sounds like something I want to try...

No, unfortunately, you can't bombard city defenses from your boat. You can however, still attack with the catapult and cause collateral damage to the defenders. And, if you're at frigates, you could potentially be bombing them from the sea before your land troops arrive, so coastal cities really need to be well defended now...