diff --git a/src/main/java/seedu/address/logic/commands/FilterCommand.java b/src/main/java/seedu/address/logic/commands/FilterCommand.java
index e574ccf4875..bf5f8fda3d6 100644
--- a/src/main/java/seedu/address/logic/commands/FilterCommand.java
+++ b/src/main/java/seedu/address/logic/commands/FilterCommand.java
@@ -2,12 +2,18 @@
 
 import seedu.address.commons.util.CollectionUtil;
 import seedu.address.commons.util.ToStringBuilder;
+import seedu.address.logic.Messages;
 import seedu.address.model.Model;
-import seedu.address.model.person.*;
+import seedu.address.model.person.Person;
 import seedu.address.model.tag.Tag;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Objects;
+import java.util.Optional;
 
+import static java.util.Objects.nonNull;
 import static java.util.Objects.requireNonNull;
 import static seedu.address.logic.parser.CliSyntax.PREFIX_ADDRESS;
 import static seedu.address.logic.parser.CliSyntax.PREFIX_EMAIL;
@@ -36,7 +42,8 @@ public class FilterCommand extends Command {
             + PREFIX_ADDRESS + "123, Tengah Ave 6, #69-420 "
             + PREFIX_TAG + "CS2103 "
             + PREFIX_TAG + "CSGod";
-    private PersonFilter personFilter;
+    public static final String CONTACTS_NOT_FILTERED = "At least one parameter is required to filter contacts.";
+    private final PersonFilter personFilter;
 
     public FilterCommand(PersonFilter personFilter) {
         requireNonNull(personFilter);
@@ -45,7 +52,10 @@ public FilterCommand(PersonFilter personFilter) {
 
     @Override
     public CommandResult execute(Model model) {
-        return new CommandResult("Filtering");
+        requireNonNull(model);
+        model.updateFilteredPersonList(personFilter::test);
+        return new CommandResult(
+                String.format(Messages.MESSAGE_PERSONS_LISTED_OVERVIEW, model.getFilteredPersonList().size()));
     }
 
     /**
@@ -60,18 +70,6 @@ public static class PersonFilter {
 
         public PersonFilter() {}
 
-        /**
-         * Copy constructor.
-         * A defensive copy of {@code tags} is used internally.
-         */
-        public PersonFilter(PersonFilter toCopy) {
-            name = toCopy.name;
-            phone = toCopy.phone;
-            email = toCopy.email;
-            address = toCopy.address;
-            tags = toCopy.tags;
-        }
-
         /**
          * Returns true if at least one field is edited.
          */
@@ -129,26 +127,26 @@ public Optional<Set<Tag>> getTags() {
         }
 
         public boolean test(Person person) {
-            if (!person.getName().fullName.contains(name)) {
+            if (nonNull(name) && !person.getName().fullName.toLowerCase().contains(name.toLowerCase())) {
                 return false;
             }
-            if (!person.getPhone().value.contains(phone)) {
+            if (nonNull(phone) && !person.getPhone().value.contains(phone)) {
                 return false;
             }
-            if (!person.getEmail().value.contains(email)) {
+            if (nonNull(email) && !person.getEmail().value.toLowerCase().contains(email.toLowerCase())) {
                 return false;
             }
-            if (!person.getAddress().value.contains(address)) {
+            if (nonNull(address) && !person.getAddress().value.toLowerCase().contains(address.toLowerCase())) {
                 return false;
             }
-            if (!tags.isEmpty()) {
-                Tag[] tagsToCheck = tags.toArray(new Tag[1]);
+            if (nonNull(tags) && !tags.isEmpty()) {
+                Tag[] tagsToCheck = tags.toArray(new Tag[0]);
                 Tag[] currentTags = person.getTags().toArray(new Tag[0]);
                 for (Tag tag:tagsToCheck) {
                     for (int i = 0; i <= currentTags.length; i++) {
                         if (i == currentTags.length) {
                             return false;
-                        } else if (currentTags[i].tagName.contains(tag.tagName)) {
+                        } else if (currentTags[i].tagName.toLowerCase().contains(tag.tagName.toLowerCase())) {
                             break;
                         }
                     }
diff --git a/src/main/java/seedu/address/logic/parser/EditCommandParser.java b/src/main/java/seedu/address/logic/parser/EditCommandParser.java
index d53ac1d43fb..7dd9f65aeda 100644
--- a/src/main/java/seedu/address/logic/parser/EditCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/EditCommandParser.java
@@ -18,7 +18,6 @@
 import seedu.address.logic.commands.EditCommand;
 import seedu.address.logic.commands.EditCommand.EditPersonDescriptor;
 import seedu.address.logic.parser.exceptions.ParseException;
-import seedu.address.model.tag.Tag;
 
 /**
  * Parses input arguments and creates a new EditCommand object
diff --git a/src/main/java/seedu/address/logic/parser/FilterCommandParser.java b/src/main/java/seedu/address/logic/parser/FilterCommandParser.java
index 2f296e87c50..53cd7a693f3 100644
--- a/src/main/java/seedu/address/logic/parser/FilterCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/FilterCommandParser.java
@@ -1,14 +1,16 @@
 package seedu.address.logic.parser;
 
-import seedu.address.commons.core.index.Index;
-import seedu.address.logic.commands.EditCommand;
 import seedu.address.logic.commands.FilterCommand;
 import seedu.address.logic.commands.FilterCommand.PersonFilter;
 import seedu.address.logic.parser.exceptions.ParseException;
 
 import static java.util.Objects.requireNonNull;
-import static seedu.address.logic.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
-import static seedu.address.logic.parser.CliSyntax.*;
+import static seedu.address.logic.commands.FilterCommand.CONTACTS_NOT_FILTERED;
+import static seedu.address.logic.parser.CliSyntax.PREFIX_ADDRESS;
+import static seedu.address.logic.parser.CliSyntax.PREFIX_EMAIL;
+import static seedu.address.logic.parser.CliSyntax.PREFIX_NAME;
+import static seedu.address.logic.parser.CliSyntax.PREFIX_PHONE;
+import static seedu.address.logic.parser.CliSyntax.PREFIX_TAG;
 import static seedu.address.logic.parser.ParserUtil.parseTagsForUse;
 
 /**
@@ -44,7 +46,7 @@ public FilterCommand parse(String args) throws ParseException {
         parseTagsForUse(argMultimap.getAllValues(PREFIX_TAG)).ifPresent(personFilter::setTags);
 
         if (!personFilter.isAnyFieldEdited()) {
-            throw new ParseException(EditCommand.MESSAGE_NOT_EDITED);
+            throw new ParseException(CONTACTS_NOT_FILTERED);
         }
 
         return new FilterCommand(personFilter);