PARIS (April 26)—Groupe Michelin reported a sales revenue increase of 14.8 percent in the first quarter, to $3.56 billion, as unit sales of tires jumped 11 percent and the euro-denominated results benefited from currency exchange parities. Unit volume was up 12.4 percent in North America, and the first-time consolidation of the tire retail chain Tire Centers L.L.C. contributed close to $50 million in new sales to the ledger, Michelin said. On the down side, Michelin reported selling prices were down, and its product mix was not optimum. Michelin did not release earnings, but said the first quarter performance put it on schedule to report operating earnings equal to 9.5 percent of sales by year-end.