They occasionally appear on eBay, but can be expensive. Had my eye on some 1:50,000's from around Caen and south over the weekend (important Canadian area) and while some of the peripheral ones went for around $25 US, the key ones were up around $90 US per sheet.
Not quite the same, but you can look at those locations on current Google (or similar) maps, which also let you see airphotos for the area (resolution varies). This site translates map references to Lat/Longs which you can feed directly to Google, etc.
http://www.echodelta.net/mbs/eng-translator.php
Your area will be the Nord de Guerre zone. You also need to figure out which square it is in from this page
http://www.echodelta.net/mbs/eng-grids.php#s4
I've never determined how to match these two letter identifiers with any of the typical map sheet data, so it's a bit of comparing to another map (say Google) to identify landmarks, etc. and a bit of experimenting to find the right one. Something obvious in a town or the like will act as a double check to make sure you aren't on in adjacent square.
From my experimenting, the coordinates generated here seem pretty accurate.