Hi Warren,
If you are looking for cemeteries like Pere-Lachaise, see the one in Vienna, the Zentral Friedhof, I was there once, it's huge, bigger than Pere-Lachaise. Like Pere-Lachaise, you will recognise the famous personalities buried there.
As for the military/war cemeteries, beside those in Normandie, the big one in northern France for the British in WW I is in Arras. Go to the tourist office in the central square in Arras where you can find out exactly where another large British cemetery from WW I, like the one in Arras, called Baumont-Hamel is located. It's near Arras. If you have a car, drive from Amiens on the Somme to Arras and you see along roads in green signs British and Commonwealth war cemetery. They dot the landscape.
East of Paris, about an hour from Gare de l'Est is Chateau Thierry, where there is a joint British-French military cemetery from WW I. If you are interested in seeing the Canadian role, again near Arras is Vimy, where the big Canadian monument is.
Luckily I was driven to see these sites outside of Arras; if you're going to pursue this in northern France, north of Amiens, you'll need a car, especially on the outskirts of towns like Albert, Cambrai, Perrone.
Happy Travels!!