Markus Brier and Robert Rock share third place at minus-5. Gregory Bourdy, Alejandro Canizares, Simon Dyson and Raymond Russell are one stroke further back at 4-under-par 67 after one round.
Cevaer got off to a quick start with birdies on the 10th and 13th as he started on the back nine at Kennemer Golf & Country Club. The Frenchman reeled off seven straight pars from the 14th.
The 36-year-old birdied three and four to move within two of Hansen. Cevaer dropped his approach shot within 4 feet of the cup at the fifth and sank that putt to make it three in a row.
Cevaer, whose lone tour win came at the 2004 Canarias Open de Espana, joined Hansen in the lead at minus-6 thanks to a 9-foot birdie putt on the seventh. He parred his final two holes to remain tied for the lead.
'I must admit that it hasn't happened for me during the summer, during the swing of all the big tournaments,' Cevaer stated. 'I wasn't necessarily playing badly. At this game, you keep plugging away.
'Look at Marc Warren last week, he has been struggling all year and then bang, he comes through with a win. I am not saying I am happy with it, it has been frustrating, but I will keep plugging away and hopefully the reward is just around the corner.'
Hansen also played the back nine first and started with a birdie on the 10th. He collected his second birdie at 16, but gave that stroke back with a bogey at the par-4 18th.
The 35-year-old rolled in an 8-foot eagle putt on the par-5 second to move to 3 under. Hansen came right back with a birdie putt from just inside 20 feet at the third.
Hansen drained another birdie putt of a similar length on the fifth. He moved to minus-6 with a birdie on the ninth, his last.
'It was a very nice round. I made a fair bit of putts, so it was a nice change,' said Hansen, who survived some heavy rain and wind at the start of his round. 'We were caught playing 11 and 12. The 12th was playing quite long. You could hardly get it to the fairway on 12. It was pretty bad there, but all in all the conditions were alright.'
The opening 66 for Hansen was even more impressive due to the fact that he had never seen the course before. He pulled out of the pro-am on Wednesday due to a sore neck.
'This is the first time I played the course today,' Hansen admitted. 'There were a few shots were I didn't know where to hit it so I just followed my caddie's advice of where to hit it.'
David Drysdale and Barry Lane lead a group of 15 players tied for ninth place 3-under-par 68.
Defending champion Gonzalo Fernandez-Castano struggled in the opening round as he posted a 4-over-par 75 and stands in a tie for 123rd.