Northern France isn't a single trip. Champagne, Normandy, Picardy each have their own bases. Here's the honest map.
Champagne — Reims or Épernay
Reims has the cathedral and the big champagne houses (Veuve Clicquot, Taittinger). Épernay has Avenue de Champagne and the grower-houses. Pick one for 2-3 nights.
Normandy — Bayeux or Caen
Bayeux is the small medieval base for D-Day beaches and the famous tapestry. Caen is the larger city with WWII museum. Bayeux is the better 2-3 night base.
Lille — for Flemish France
Lille's Vieux Lille is the Flemish-influenced old town. Best for: 2-night weekend stays, food-focused trips, train-from-London (Eurostar 1h 30min).
Calais and Boulogne — only for Eurotunnel transit
Skip both as destinations. Worth a stop only for ferries to UK or Eurotunnel arrival.
Strasbourg — Alsace, technically east not north
Strasbourg deserves its own 2-3 night focus. See Strasbourg guide.
Combined 7-day Northern France
- Day 1-2: Lille (with day-trip to Brugge if Eurostar-easy)
- Day 3-4: Reims + Épernay champagne
- Day 5-7: Bayeux + D-Day beaches
What to skip
- Mont Saint-Michel as same-day from Bayeux: Possible but eats time. Stay overnight nearby.
- Saint-Malo for short trips: Beautiful but adds Brittany detour.