I stayed legally in France for 6.5 years as a student. I then overstayed my french student Visa for 6 months in 2013. I left france voluntarily. The french immigration only asked me why didn't I apply for extension, I said I was promised a job but in the end I got betrayed by my employer. She said ok, she didn't said anything about a ban, I didn't sign any paper. I just boarded my flight.

But now I want to visit my sister in the UK for a week. I checked the UK Visa website and they asked about last 10 years travel history and if you have overstayed. 

I live in Dubai now for the last 3 years, I have a good job which pays me more than the minimum wage of the UK. I have good friends here and professionally too. I have rent agreement under my name and I have paid the full rent for the year. I really love dubai and I never want to stay in the UK for more than a week.

My questions are:

* Will they know my overstay if I do not mention it on the application
form?
* If I do mention it, how can I justify it?
* How can I prove my intentions to come back, which is the truth.