Happn, which recently announced its millionth user worldwide and has over 100,000 members in London alone, enables users to view the profiles of people who have come within 250m of them.
"PHA will be responsible for positioning Happn as a key player in the UK online dating market, as well as raising its profile as the more romantic, real-world alternative to competitors," the agency said.
Marie Cosnard, head of communications at Happn, said: "We've been really lucky with a great response in the UK so far, but wanted to maximise our presence and were looking for a partner that could help us take control of our image across the pond. We were really impressed by PHA’s enthusiasm and creative flair, and are looking forward to some exciting campaigns in the New Year."
Nick Braund, who heads up the Technology & Innovation team at PHA, said: "The dating world has been revolutionised by the rapid growth of apps, but Happn’s proposition keeps the digital to a minimal so that people can enjoy real-world connections. It’s a great model and one we’re confident will continue to capture hearts across the nation."
PHA’s other new client, Chipolo, is said to be the first bluetooth tracking device company based in Europe. It is selling its products across the world after recently raising $290,000 (£185,600) in crowdfunding, 12 times the initial target.
Tadej Jevsevar, VP of sales for Chipolo, said: "We believe that the UK market is absolutely vital for Chipolo. We want to be the the market leaders for bluetooth tracking devices with our innovative new product. We are the only providers of this technology within Europe and want to help the British public never lose anything again.
We chose to work with PHA Media as a result of their great ideas and mainstream consumer and tech contacts, helping to put us in the minds and media of people throughout the UK."
Braund said: "Wearable technology is one of the most exciting areas in the media today and we’re delighted to be working with Chipolo to bring their product to the UK. We have all experienced the dread of losing a valuable item and we know that Chipolo can stop anyone having this fear again.
"This is another fantastic addition to our growing technology client base, working and generating quality coverage with some of world’s most innovative companies to spread and share their message."
Earlier this year PHA hired former head of business news for Telegraph Media Group, Tim Jotischky.