[OT] - remote assistance software

I'm sorry for the OT but I thought that some of you could spare me tons of time. Do you know any very good open source software for remote assistance that runs on debian (my side) and windows > 7 (customer side). I need to be able to control kbd and mouse and see customer's screen. Depending on price I definitely consider paid versions and I would avoid any cloud service (unless there is no other valid option) that I can not control. Time ago I used the google chrome extension but last time I used it gave me troubles and, in any case, I would definitely go for something more professional. Thanks! -- Damiano Venturin https://dam.venturin.net