Bring a large pot of salted water to a boil. Add the haricots verts and cook until crisp-tender, about 4 minutes. Drain, then plunge into an ice bath to stop the cooking. Drain again, then transfer to paper towels and pat dry.
Cook the pancetta in a large skillet over medium heat, stirring occasionally, until crisp, about 8 minutes. Remove to paper towels using a slotted spoon. Add the garlic to the drippings in the skillet and cook, stirring, until golden, about 1 minute. Add the panko and cook, stirring, until toasted, about 1 minute.
Add the haricots verts to the skillet and cook, stirring, until evenly coated, about 2 minutes. Stir in the pancetta and season with salt and pepper. Serve with lemon wedges.