No, property sales appear to have risen from what I hear at home. However, whilst there are still people coming from the UK, some of whom riding on the present exchange rate and speculating on better by completion of buying, there are far more French people buying than before in this area. Also, other European countries really are on the move, plus of course the Chinese and Russians buying up for investment and to get rid of taxable money in foreign, more or less untouchable, property.
How could tourism be affected really? Perhaps if the £ takes a big hit it might become more expensive and all the old benefits of cheap wine and sausages be lost. Inevitably the Chunnel will change in that the UK customs and immigration will be pushed back over to the other side although the government tries to convince everybody that will not happen.
Customs and police have collaborations that have nothing to do with the EU that will continue unless the loonies in the UK bring their country out of the WCO and Interpol. You never know after listening to some of them though!