Retail sales in the Washington metropolitan area in July ran 12 per cent ahead of last year and the latest unemployment figures for the area are a full half point better than the previous year.

But department stores in the District reported their sales were down from the previous year and the D.C. jobless rate remained almost twice as high as that of the entire area.

The unemployment statistics from the D.C. Department of Manpower showed the metropolitan area, seasonally adjusted unemployment rate in August remained 4.5 per cent, the same as in July, but down from 5 per cent a year ago.

In Washington itself, however, seasonally adjusted unemployment in August increased from July's 7.9 per cent to 8 per cent, but was still a full point better than in 1976.

Total employment in the metropolitan area in August was down 5,000 workers from July to 1,423,000 jobs. The number of people looking for work but unable to find it was down 1,700, to 69,300.

The D.C. figures showed total employment down by 1,100 jobs to 312, 400 and umemployment down by 700 to 27,700.

Despite the smaller work force and nearly flat jobless rate, retail sales in the metropolitan area were $95 million ahead of last year, totalling $902 million. Total retail volume for the first seven montsh of the year also was 12 per cent ahead of the prior year. Most of the July gain was in nondurable goods sales, up $54 million to $598 million.

Sales figures for department stores showed a 13 per cent increase over July a year ago, and an 11 per cent gain for the first seven months of the year. The total was almost $113 million for the month, compard to $99.7 million a year ago.