How can you tell when poursuivre means to sue or to chase after? In some of the examples it could be either

Hi Johanna,

I think you would know from the context whether it meant to chase after or to sue someone...

For to sue you could also say -

Poursuivre en justice 

Je l’ai poursuivi ( en justice) pour diffamation = I sued him for libel

Or you might use -

Engager des poursuites = to start proceedings

Sometimes poursuivre just mean to continue -

Avant de poursuivre , j’aimerais que ...= Before we carry on, I’d like...

So a very useful verb to learn...