Property group Hammerson saw an increase in demand for office space in the first quarter but occupancy rates at its retail assets in the UK and France were marginally lower.Overall occupancy across the portfolio improved to 95.3% at the end of March from 95.2% at the end of 2009."Our recently completed developments at 60 Threadneedle Street and 125 Old Broad Street, London EC2 ... are now 100% and 92% let or in solicitors' hands respectively," the company said.The occupancy rate for its office properties climbed to 94.5% from 91.6%, but the UK retail occupancy rate dipped to 94.0% from 94.5% at the end of 2009 while the French retail occupancy rate edged lower to 98.2% from 98.5%.Rent collection rates remained healthy, with 97% of UK rent collected within seven days over the quarter, while the equivalent French rate was 93%.The UK shopping portfolio generated a 1.7% like for like (LFL) increase in sales over the quarter but the French portfolio saw a 0.5% fall in LFL sales.The number of retail units in administration declined to 58 at the end of March from 64 at the end of 2009.Net debt at the end of March held steady at £2.1bn while cash and untapped facilities stood at £766m.The company said it has seen a rise in the value of its commercial properties over the first three months of 2010 which has led to an increasing number of properties coming on to the market.In France, where the downturn in property values was less severe than in the UK, "there was limited investment activity but recent evidence suggests that values were largely unchanged over the period," the company said.