Total group revenues rose to £38.4m during the period, up 16.2 per cent from the same quarter last year.
That was pushed up by a 28.5 per cent increase in property sales commissions ahead of the new buy to let rules (more on which later) - although lettings revenue was flat.
Meanwhile, revenues at Alexander Hall, the company's mortgage broker, rose 57.6 per cent in the quarter.
But investors weren't impressed: shares fell 2.3 per cent to 151.75p in early trading.
Why it's interesting
It seems Foxtons was one of the chief beneficiaries of the scramble by wannabe landlords to get their transactions in before 1 April, when the chancellor imposed a three per cent hike on stamp duty for buy to let homes.
Such was the intensity of the frenzy, it caused house prices to spike in the months before the deadline - but analysts have suggested the rise was temporary, hence today's fall in shares.
There are also concerns about the impact of a potential Brexit on the market. "Foxtons will, in our view, need to be slicker than its own sales teams' shiny suits to perform well in the lead-up to the EU referendum," said Anthony Codling, equity analyst at Jefferies International.
Various organisations have predicted that house price growth in the capital will weaken this year as demand falls thanks to uncertainty over the Brexit and tighter regulations on borrowing.
"It is our assessment that the London market is most at risk from a slowdown in buy to let activity (widely expected following stamp duty changes) and EU referendum housing transaction paralysis," added Codling.
"Foxtons has had market led profit downgrades in the past and, in our view, it is the UK estate agent most risk of having one in the near future and it appears that the slowing market is currently outweighing the impact of organic growth."
What Foxtons said
Chief executive Nic Budden was realistic about the next few months.
"We have had a strong start to the year with a record first quarter driven by a number of sales transactions being brought forward before the introduction of the additional stamp duty surcharge on buy-to-let properties.
"Nevertheless, we expect the first half of the year to be challenging with a reduced sales pipeline entering into the second quarter and the underlying short term impact on transaction volumes from the uncertainty around the European referendum. Our expansion strategy remains on track as we continue to increase our market share in outer London."
A strong first quarter for Foxtons - but thanks to Brexophobia, the next part of the year is likely to be challenging.