The Challenge Tour graduate's 62 at Hilversumsche Golf Club put him two shots ahead of England's Kenneth Ferrie during the opening day in The Netherlands.
Colsaerts, the longest driver on The European Tour this season, reached the turn in 33 but burst to life on the back nine with birdies at the 11th, 13th and 14th before his closing hattrick that ensured the lowest round of his European Tour career.
"It's like a home tournament for me and I grew up playing very similar courses in Belgium so I feel very comfortable here in this course with the trees everywhere and a very traditional layout," said the 27 year old.
"There have been some changes here and they have done them very well. I love these courses because I am so used to the layouts."
Colsaerts is yet to win a European Tour title, but believes his game is getting close to where it needs to be.
"This is my first year back on Tour for three years and it has been very good for me to be able to come back out and feel comfortable straight away and start to get some good results," he said.
"I am realising again that I can compete at the highest level. I am still not happy with the level of my chipping and putting but I am always working on that."
Former European Open winner Ferrie is currently 110th on The Race to Dubai and aware that a good performance this week could ease the anxiety surrounding his playing card for next season, with only the top 115 retaining playing privileges.
A closing eagle on the par five last certainly helped his cause, having been preceded by five birdies and a bogey.
Ryder Cup debutant Ross Fisher was part of a five-way tie for third on five under, along with fellow Englishman Nick Dougherty, Argentine Tano Goya, France's Raphaël Jacquelin and Scot Richie Ramsay.
Defending champion Simon Dyson enjoyed an unusual round - the Englishman did not deviate from par on a single hole in his opening 70.
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