"As a cop, you see what bad things people are capable of," Mr French said. "But, at the gym, you see a lot of the good things.
"In four weeks, I've seen principals, business people and nurses all exercising together, high fiving and slapping each other on the back.
"It doesn't matter if a person finishes last, they still get a huge cheer - gives you goosebumps every time.
"We started the gym to help nurture community spirit - it's great to see."
Mr French first discovered CrossFit - an exercise philosophy with elements of interval training, weightlifting, gymnastics and calisthenics - eight years ago, while studying at the Royal New Zealand Police College.
He and Ms Parata, a personal trainer, started attending WOF CrossFit gym in Porirua and "became hooked", eventually getting their sons, aged 10 and 12, involved.
When the couple arrived in Wairarapa last year, they were unable to find a CrossFit gym which "met their needs" - so decided to start their own.
"We wanted to go for something with more of a laid-back, communal feel, rather than a boot camp," Mr French said.
"Our vision was for people to get to know one another while training."
The gym is "not flash": with basic equipment, few workout machines, no mirrors, DB Draught beer kegs for clients' pushing exercises and crates for box jumps.
"It's back-to-basics, which is part of the appeal."
Gym users range in age "from early 20s to late 40s" - though children are also welcome, with Mr French organising scooter races and competitive Easter Egg hunts.
He says people come to CrossFit with varying fitness backgrounds, and workouts can be adapted according to ability.
"People say CrossFit is hard - but you just go at your own pace.
"Anyone can do it: you can be a sportsperson or a housewife."
Mr French holds classes three hours a day during the week, and one hour on Saturday - and is having no problems running the gym around his policing schedule.
"Every day, we're meeting new friends, so I don't see it as work.
"Plus, I can relate to the community in a different way.
"People meet me, see I'm a cop, and realise we're human after all."