We've been eating at Petit Paris for many years and I can't recall either a bad meal or indifferent service.
The three course 'lunch/pre-theatre' menu is excellent value at £13.95 with a wide choice of standards and daily specials. Unusually, it is possible to upgrade to virtually any dish on the full menu for a very reasonable supplement.
Despite the name, Petit Paris is not very (Paris) French - it is more Franco-Italian (with shades of Provence). Reliable standards include mussels, minute steak frites, fish of the day, lasagne and tagliatelle. Starters often include really nice terrines. Sweets are like works-of-art..
It's very busy at lunchtime but it's a happy buzz and no matter how busy they are we always get the right dish, promptly and correctly cooked. It's best to book for both lunch and pre-theatre.