* Value of permits falls 10.3 pct vs forecast of 3.2 pct drop
* Residential permits down 12.9 pct
* Nonresidential permits decline 6.1 pct
OTTAWA, Aug 7 (Reuters) - The value of building permits taken out by contractors in Canada fell in June for the first time in six months, dropping 10.3 percent on downturns in both residential and nonresidential construction, Statistics Canada said on Wednesday.
Market players had forecast, on average, a 3.2 percent decline in permits in the month. Statscan revised the May data to show an increase of 5.8 percent in the value of building permits that month, rather than 4.5 percent as initially estimated.
An early indicator of construction activity, the permits report pointed to a slowdown in the country's heated housing market, which had appeared to gather momentum again in recent weeks after a period of cooling.
Permits issued for the residential sector fell 12.9 percent in June, with multi-family dwellings down 18.8 percent and single-family dwellings decreasing 7.4 percent.
The province of Ontario, where a condominium boom in Toronto has worried policymakers, posted the biggest decline. Permits for multiple-family dwellings in Toronto - which includes apartments and condos - fell 29.6 percent in the month.
The number of new dwellings authorized by municipalities nationwide in June fell 12.2 percent from May.
In the nonresidential sector, permits fell 6.1 percent as a downturn in commercial and industrial projects outweighed an increase in plans for institutional buildings like schools and healthcare facilities.