The District government has boosted assessments of residential property by an average of 4.3 percent, with some areas registering increases of as much as 24 percent, which city officials say reflects a continued improvement in the city's real estate market.

Commercial properties, particularly new and recently renovated hotels, were hardest hit by the new assessments, experiencing an average increase of 11 percent. Assessments of hotel property rose an average of 35 percent, with some properties reassessed by more than 50 percent.

The D.C. Department of Finance and Revenue touched off a controversy last year by proposing massive increases in the assessments of downtown properties to bring them closer to the true market values.

City officials said those increases averaged about 30 percent, but some hotel owners complained of receiving increases of 80 percent to 100 percent.

The D.C. Board of Equalization and Review reduced many of the large assessments on appeal. Robert L. King, an associate director of the Department of Finance, said his real estate experts have reviewed that property and concluded the city was entitled to recover some of the ground it lost during last year's appeal process.

"The idea is to be completely neutral, and we've really done an extensive job of it," King said yesterday. "There have been a lot of hotel sales in the last year that confirm our increased assessments."

The Department of Finance this week mailed out 1986 tax year assessment notices to the city's 155,000 taxable real property owners. The assessments, which are subject to appeal, are used as a base in computing annual tax bills.

The new assessments of owner-occupied residential property ranged from an increase of 24 percent in the Massachusetts Avenue Heights area of northwest and Barry Farms in Southeast to a decline of less than a percentage point in the Foxhall Road area in Northwest.

The Massachusetts Avenue Heights area -- the costliest in the city -- was hardest hit. The average assessment on a single-family home there rose by more than $100,000, from $398,594 to $498,807.

"It has been an uneven recovery economically," King said of the unusually large increase. "We found the same thing happening in Georgetown and made that adjustment last year. It's just that the market sales are showing that increase."

Residential assessments rose 6 to 7 percent in Chevy Chase, Cleveland Park and the upper 16th Street area in Northwest and between 10 percent and 18 percent in Kalorama, Burleith, Colonial Village, Randle Heights, Trinidad and Riggs Park.

Areas showing virtually no increase in assessed value include Anacostia, Capitol Hill, Fort Dupont Park, Hawthorne, LeDroit Park, Michigan Park and Takoma Park.

The average assessment of apartment buildings and other nonowner-occupied property increased by 4.9 percent.

Property taxes are paid in two yearly installments. The first bill to be paid under the new assessments will be due in September.

Property owners may appeal to the Board of Equalization. Forms are available in Room 2066 of the Municipal Center and public libraries.