Region encoding is independent of picture format (which, on these DVDs is NTSC, the North American and Japanese standard). Region 0 is flagged for play in all regions and therefore free of restriction.
 

All DVD players will read NTSC format discs and many will have a menu option to allow output of NTSC as pseudo PAL. The limiting factor for Europe is the TV itself as some older sets may not display NTSC pictures at all or will only render in black and white.