Hi Yousef! 
It does appear as though Framer does support the ability to copy from Sketch documents and paste into Framer.
While in Framer, you can go to the Framer menu, select “File” and “Import from Sketch”.
In the popup that appears, you can download a Sketch Plugin and copy and paste layers between Sketch and Framer.
In terms of the plugin itself, that is Framer’s plugin and so they will be the ones that created and maintain it. Because of our open file format, it makes this kind of thing nice and easy for Framer.
I hope this information helps! 