He was technically in breach of contract.

严格按照法律条文来讲,是违约。

He was sued for breach of contract.

不履行合同被起。

I sued for breach of contract.

我为毁约起。

I sued for breach of contract.

我控对方违反合同。

The auction house would be unlikely to sue him for breach of contract and in such cases usually turns to the underbidder to take the items.

佳士得不太可能违约起，在这种情况下拍品一般会转给低价竞标者。