[Adrig]

It is, tho. Diplomacy is a sensible thing. It's not as much about the contract lost, but the way it was handled. The contract was also a key piece for a deeper collaboration in the pacific area, one of the most important geopolitical sectors for the next 20 years. France shared highly confidential material for months, while Australia already had decided to breach the contract. In international relationships among allies where trust is crucial, it's pretty big.

[bodge5000]

As I said, France has not been a strong ally of the UK (again, cant speak for US or Aus, but may be a similar situation there) in the past or even very recently, why you would expect differently the other way around I don't know.

Also doesn't look like this was a "breach" of contract, just a cancellation. A breach implies what was done is illegal in international law, a cancellation implies they simply went elsewhere.