A grammar rule (Present perfect)

Is this rule correct?

when 'for' and 'since' are used in a sentence(in present perfect tense) to show duration of an action they imply that the action is still in progress. Without the 'for', the last sentence suggests that the person doesn't live in Paris anymore and that the action is complete.

I have lived in Paris for two weeks.

I have lived in Paris.

Answer

Context is king. I have lived in Paris for two weeks could mean that the speaker is no longer living there, but will not normally do so. I have lived in Paris, without further elaboration, will almost certainly mean that the speaker is now living elsewhere.