Paulinho spent two years at White Hart Lane, but after failing to live up to expectations, the midfielder moved to Chinese club Guangzhou Evergrande in 2015 and earned a switch to Barca in the summer.
Dier worked alongside the Brazilian during the 2014-15 campaign and is excited to see the 29-year-old again.
"He's been on a world tour, hasn't he? He's gone from China, now back to Europe with Barcelona," Dier told Tottenham's official website. "It's great that he's in the Brazil squad and at Barcelona - it's fantastic for him and it'll be nice to see him again.
"It's always enjoyable when you play against players who you've shared a locker room with - to meet them further down the line is always nice.
"He's done very well in the last few years and I'm really happy for him. He was always very good to me when I first arrived at Spurs. We spent one season together and he's a really nice guy."
Dier had the captain's armband for Friday night's goalless draw with Germany.