You can live with your partner under three different sets of conditions and rules. Here is an overview.

If you move in with your boyfriend or girlfriend and you don't register with the municipality as officially cohabiting, you're forming a 'de facto' (unofficial) family. The advantage: you enjoy greater freedom than with other forms of cohabitation.

As far as the tax authorities are concerned, you and your partner are two separate people. Even if you have a cohabitation contract drawn up, you both fill in a separate tax return. If you have one or more children together, you specify which of you will take responsibility for the children.

If you're cohabiting unofficially, you can't inherit from one another. If you want to change this, have the notary-public draw up a joint will. But beware: with this form of cohabitation, you'll have to pay more inheritance tax if you or your partner dies.

If you decide to split up, you can normally just walk away. If you live in a place your partner has bought or is renting in his or her name, unfortunately, you could just find yourself on the street. In that case, all you have to do is pass on your new address when you find somewhere.

You can cohabit officially through a statement of legal cohabitation given in the presence of the official registry office for your place of residence. With this option, you get more protection than if you cohabit unofficially. Together you have almost the same rights and obligations as a married couple.

Although you're still in control of your own income, you have to use part of it to cover household expenses. If either of you incurs a debt, the other one is also liable for it.

However, under this system, your home has the best possible protection. Neither of you can suddenly decide to sell, rent out or give away your home. Even if you or your partner are the sole owner.

If you would prefer to enter into an agreement specially tailored to your situation, ask the notary-public for a cohabitation contract together. Obviously, you can't put anything illegal in it, such as a clause requiring you to stay faithful to one another. If you want that, marriage may be a better option.

If you're officially cohabiting, for the first year, as far as the tax authorities are concerned, you're still two single people. Result: you both have to fill in separate tax returns. If you already have children together, only one of you can take responsibility for them. If your partner's net income is below 3 110 euros that year, you'll also get a higher tax allowance for that first year.

Different arrangements apply after that. You fill in a joint return and one of you takes responsibility for the children. That person is considered as the head of the household.

Unlike couples cohabiting unofficially, partners cohabiting officially automatically inherit from one another. There's no need to make a will. However, the inheritance is limited: the surviving partner gets the use of the home and contents. Not all of the property. If you would rather others inherit, you should make a will.

Fortunately, there's little paperwork involved. Just visit the registry office for your place of residence and sign a declaration signifying the end of your cohabitation.

The rules are different for married couples. Positive factor: this status gives you the most protection. The flipside is that this comes with greater obligations.

In practice, all rights, obligations and tax rules depend on the chosen marital regime.

• Legal system
• Joint ownership of property
• Division of goods

When one of you dies, the marriage is officially ended. But, unlike partners cohabiting officially, married couples cannot simply disinherit one another. Unless there are special circumstances. The rules of inheritance also vary depending on the system under which you are married. Ask you notary-public or  bank adviser for details.

You can end your marriage by filing for divorce. Once your divorce is final, your marriage ends. Together with the rights and obligations under your chosen marital regime (system).

In essence, cohabiting officially and living together as a married couple are more formal than cohabiting unofficially. There are a number of similarities between official cohabitation and marriage:

Both married couples and partners officially cohabiting are entitled to the married persons' allowance. This only applies if your partner has no earned income. Of if he or she has an income not exceeding 30% of your joint income. Useful, as your other half can claim part of your income for tax purposes. Result: the total amount you have to pay in tax is a lot lower than if you were two single people.

If you are getting married or just going to cohabit officially, as far as the tax authorities are concerned, you're two single people. You each fill in a tax return. Even if you already had a child before you got married, only one of you can take responsibility for them. If your partner's net income is below 3 110 euros that year, you'll get a higher tax allowance for the first year of your marriage.

Different arrangements apply after that and you have to fill in a joint return. One of you takes responsibility for the children, usually the one with the higher income.

If you take out an mortgage loan as an officially cohabiting or married couple, you can decide how the charges for the loan are divided. This includes the principal repayment, interest and premiums for the loan balance insurance. You fill this in on your tax return.

As a married or officially cohabiting couple, you are jointly responsible for any debts. Even if your partner has created them. On the other hand, unofficially cohabiting couples enjoy more freedom in this area.