I'm non-EU, currently living in Marseille with my British partner. We are getting married in the fall. We have a lease together for the place we live in. I currently do not have a French visa or legal status here.
I need to travel to Bilbao for work before we get married, and I'm unsure whether to travel by plane, because I know that at the Marseille airport they randomly enforce immigration passport control even for flights within the EU. If they check my passport, they will see I have overstayed in France and I have no tangible proof of my relationship with my fianceé other than our rent lease and receipts, and by the time of my trip we will have submitted our marriage dossier, so I suppose I will have some proof of that.
Can anyone advise if it's recommended I book a flight? Will immigration detain me? Or give me a fine? Should I not travel at all?
Thanks a lot.