Lucie a été voir un film. -- Lucie went to see a movie. Literally, this would be "Lucie was to see a movie." Your suggestion, Lucie est allée voir un film, is, of course, straightforward and also correct.

If you look at the same passage on the blog, you can see that this question has been asked before. However I don't totally agree with Aurélie's answer - you can't say "Lucie has been to see a film" in this context, it would have to be "Lucie had been to see a film". It seems to me as if a present tense is being used in a narrative, which is of course more common in French than English.

https://kwiziq.learnfrenchwithalexa.com/blog/la-semaine-des-martin/

Strictly grammatically speaking, a été is passé composé.

Of course, and "has been" is the "present perfect". But I mean that its use here seems to me like the présent historique. 

I see what you mean, but I don't think that a été voir... carries the implied meaning of past perfect tense here. But maybe my German speaking roots bias my interpretation of the French. I think it simply means "she were to see..." (not proper English, I know, just to illustrate what I mean). If you wanted to say "she had been to see..." you'd use avait été voir...

In general, the passé composé can be interpreted as either the present perfect or a simple past tense. Aurélie interpreted it as the present perfect: "she has been to see", and I can't see how to interpret it as the simple past. Neither "she was to see" nor "she were to see" make much sense to me. The former sounds as if it was something still in the future.

When you use the historic present, a present tense is used to substitute for a simple past tense. In the same way, a present perfect tense can substitute for a past perfect. However, since the rest of the story is told in the passé composé, I think "avait été voir" might have been more correct.

I have the same question. Why wouldn't it be "Lucie Martin est allée voir" ? "Aller" in the Passé Composé always takes être as the helping verb.