Mix cream cheese, 150 g crème fraîche and horseradish. Wash the herbs, dab dry, put some dill aside for garnishing. Chop the chives in small rolls, dill finely. Cut cream cheese cream in half. Stir the herbs under one half.
Season both creams with salt and pepper. Line a box form (bottom 22 cm, top 23 cm long; 1.25 litres capacity) with cling film. Put half of the white cream into the tin and smooth it down. Cover with 2 slices of bread, cut them into pieces if necessary. Stir 100 g crème fraîche until smooth. Spread 1/3 on the bread, cover with about 60 g salmon. Put half of the herb cream on top and smooth it down. Layer the remaining crème fraîche, bread, salmon (up to 60 g) and cream cheese cream. Cover with foil and chill for about 1 hour. Remove the terrine from the mould and remove the foil.
Spread 1/3 on the bread, cover with about 60 g salmon. Put half of the herb cream on top and smooth it down. Layer the remaining crème fraîche, bread, salmon (up to 60 g) and cream cheese cream. Cover with foil and chill for about 1 hour. Remove the terrine from the mould and remove the foil. Cover with remaining salmon slices. Garnish the terrine with lemon wedges and dill