Entering the french tax system

Hello. Myself and my husband have been paying Tax & NI in the uk for the past however many years but really this year we should, as we now live here, think about declaring over here. Is it an easy process to transfer over ? We were both self employed musicians in the Uk, but due to a serious illness have now retired ( since dec 2012 ) . He has his UK pension and a few private pensions but I am 57 so under retirement age. We have a property in the Uk which we rent out so have a monthly income from that. I haven't a clue as to where to start ! We've just received our self assessment forms from the Uk - mine is the usual that I've filled in for the past few years but his was just "Residence, Remittance basis etc " I'm used to self assessment so really would like to manage myself. Is it v v complicated ???