"3 Sisters" and "The Importance of Being Earnest"
"Scene Study" is the next step after your monologues (comedy & drama -- you have to have two monologues at least).
You need to know something about how to develop your character -- and you need a partner.
How to select the text? Do the cold reading. Do it together. Do it for some public. Anybody.
There are many great scripts online, there are many books in the library. Read the whole play, if you want to do the scene from the play... and do it right.
Read, think, try -- and talk about it.
Make sure that you have what you must have -- the dramatic structure (Exposition, climax, Resolution). Do you know where it is in your scene?
Try it on your feet, try improv. Yes, put the text away and try the scene in your own words.
What is "french scene"?