Geneva is expensive — eating out is one of the more painful aspects of visiting — but the city does have a worthwhile food scene if you know where to look. Local Swiss food centres on fondue (melted Gruyère and Vacherin with white wine), raclette (melted cheese scraped onto potatoes), and filets de perches (perch fillets from the lake, traditionally fried and served with sauce). The Café du Soleil in Petit-Saconnex is widely considered the city's best fondue. For perch, lakeside restaurants in Eaux-Vives or the smaller venues in Cologny across the bridge are the classic spots.
The city's diversity — over 40% of residents are foreign nationals — means strong Italian, French, Spanish, Lebanese, and Ethiopian options. The Pâquis quarter has the densest mix: Lebanese mezze houses, Senegalese restaurants, and reliable pizza places, mostly at prices that locals can actually afford.
For something specific to Geneva, the longeole (pork-and-fennel sausage from the canton) is a regional specialty served in old-town bistros. The Plainpalais quarter and Carouge (which calls itself "the little Sardinia") have more relaxed and slightly cheaper eating — Carouge in particular has a clutch of trattorias and wine bars where you can dine well for under CHF 50.
Reservations are advised in the evening. Plats du jour at lunchtime are the cheapest way to eat well — typically CHF 18-25 for a substantial main course.